Programa escolar (Estados Unidos)

Matemáticas — 8.º grado

Matemáticas de 8.º grado según los Estándares Estatales del Tronco Común: exponentes, raíces cuadradas y cúbicas, notación científica, ecuaciones con variables en ambos lados, sistemas de ecuaciones, funciones lineales y pendiente, el teorema de Pitágoras y el volumen de cilindros, conos y esferas. Cada tema incluye hojas de trabajo imprimibles listas para usar.

Crear una hoja de este programa

¿Qué aprende un estudiante en matemáticas de 8.º grado?

En 8.º grado, el estudiante trabaja con exponentes enteros, raíces cuadradas y cúbicas y notación científica. Las ecuaciones tienen variables en ambos lados y se resuelven dos ecuaciones como un sistema. Las funciones se convierten en la idea principal: el estudiante identifica la pendiente y la intersección con el eje y de una recta y evalúa funciones lineales. En geometría, el teorema de Pitágoras permite hallar lados desconocidos, y el estudiante calcula el volumen de cilindros, conos y esferas.

Estado de la página: exponentes y raíces, notación científica, porcentajes, operaciones con números con signo, ecuaciones y sistemas, funciones lineales, el teorema de Pitágoras, círculos y sólidos, y probabilidad están listos. Las transformaciones y los diagramas de dispersión se agregarán a continuación.

Alcance del currículo

Punto del currículo 8.NS · Contenidos de enseñanza · verificado con el texto oficial

El sistema numérico

nuestra traducción · texto original (EN): The Number System

CCSS Mathematics (2010), Grade 8, domain The Number System (8.NS)
Punto del currículo 8.NS.A · Contenidos de enseñanza · verificado con el texto oficial

Saber que hay números que no son racionales, y aproximarlos mediante números racionales.

nuestra traducción · texto original (EN): Know that there are numbers that are not rational, and approximate them by rational numbers.

CCSS Mathematics (2010), Grade 8, The Number System, cluster A
Punto del currículo 8.NS.A.1 · Contenidos de enseñanza · verificado con el texto oficial

Saber que los números que no son racionales se llaman irracionales. Comprender de manera informal que todo número tiene una expansión decimal; para los números racionales, mostrar que la expansión decimal finalmente se repite, y convertir una expansión decimal que finalmente se repite en un número racional.

nuestra traducción · texto original (EN): Know that numbers that are not rational are called irrational. Understand informally that every number has a decimal expansion; for rational numbers show that the decimal expansion repeats eventually, and convert a decimal expansion which repeats eventually into a rational number.

CCSS Mathematics (2010), Grade 8, The Number System, standard 8.NS.A.1
Punto del currículo 8.NS.A.2 · Contenidos de enseñanza · verificado con el texto oficial

Use rational approximations of irrational numbers to compare the size of irrational numbers, locate them approximately on a number line diagram, and estimate the value of expressions (e.g., π 2). For example, by truncating the decimal expansion of √2, show that √2 is between 1 and 2, then between 1.4 and 1.5, and explain how to continue on to get better approximations.

CCSS Mathematics (2010), Grade 8, The Number System, standard 8.NS.A.2

Estimating Square Roots (en nuestro curso 8)
Punto del currículo 8.EE · Contenidos de enseñanza · verificado con el texto oficial

Expressions and Equations

CCSS Mathematics (2010), Grade 8, domain Expressions and Equations (8.EE)
Punto del currículo 8.EE.A · Contenidos de enseñanza · verificado con el texto oficial

Trabajar con radicales y exponentes enteros.

nuestra traducción · texto original (EN): Work with radicals and integer exponents.

CCSS Mathematics (2010), Grade 8, Expressions and Equations, cluster A
Punto del currículo 8.EE.B · Contenidos de enseñanza · verificado con el texto oficial

Comprender las conexiones entre las relaciones proporcionales, las rectas y las ecuaciones lineales.

nuestra traducción · texto original (EN): Understand the connections between proportional relationships, lines, and linear equations.

CCSS Mathematics (2010), Grade 8, Expressions and Equations, cluster B
Punto del currículo 8.EE.C · Contenidos de enseñanza · verificado con el texto oficial

Analyze and solve linear equations and pairs of simultaneous linear equa-tions.

CCSS Mathematics (2010), Grade 8, Expressions and Equations, cluster C
Punto del currículo 8.EE.A.1 · Contenidos de enseñanza · verificado con el texto oficial

Know and apply the properties of integer exponents to generate equivalent numerical expressions. For example, 32 × 3 –5 = 3–3 = 1/33 = 1/27.

CCSS Mathematics (2010), Grade 8, Expressions and Equations, standard 8.EE.A.1

Using Rules of Integer Exponents (en nuestro curso 8) · Understanding Negative Exponents (en nuestro curso 8) · Evaluating Powers of Integers and Fractions (en nuestro curso 8)
Punto del currículo 8.EE.A.2 · Contenidos de enseñanza · verificado con el texto oficial

Use square root and cube root symbols to represent solutions to equations of the form x2 = p and x3 = p, where p is a positive rational number. Evaluate square roots of small perfect squares and cube roots of small perfect cubes. Know that √2 is irrational.

CCSS Mathematics (2010), Grade 8, Expressions and Equations, standard 8.EE.A.2

Finding Square Roots and Cube Roots (en nuestro curso 8)
Punto del currículo 8.EE.A.3 · Contenidos de enseñanza · verificado con el texto oficial

Usar números expresados en forma de un solo dígito multiplicado por una potencia entera de 10 para estimar cantidades muy grandes o muy pequeñas, y para expresar cuántas veces mayor es una que la otra. Por ejemplo, estimar la población de los Estados Unidos como 3 × 10 8 y la población del mundo como 7 × 10 9, y determinar que la población mundial es más de 20 veces mayor.

nuestra traducción · texto original (EN): Use numbers expressed in the form of a single digit times an integer power of 10 to estimate very large or very small quantities, and to express how many times as much one is than the other. For example, estimate the population of the United States as 3 × 10 8 and the population of the world as 7 × 10 9, and determine that the world population is more than 20 times larger.

CCSS Mathematics (2010), Grade 8, Expressions and Equations, standard 8.EE.A.3

Working with Scientific Notation (en nuestro curso 8)
Punto del currículo 8.EE.A.4 · Contenidos de enseñanza · verificado con el texto oficial

Perform operations with numbers expressed in scientific notation, including problems where both decimal and scientific notation are used. Use scientific notation and choose units of appropriate size for measurements of very large or very small quantities (e.g., use millimeters per year for seafloor spreading). Interpret scientific notation that has been generated by technology.

CCSS Mathematics (2010), Grade 8, Expressions and Equations, standard 8.EE.A.4

Working with Scientific Notation (en nuestro curso 8)
Punto del currículo 8.EE.B.5 · Contenidos de enseñanza · verificado con el texto oficial

Representar gráficamente relaciones proporcionales, interpretando la tasa unitaria como la pendiente de la gráfica. Comparar dos relaciones proporcionales diferentes representadas de maneras distintas. Por ejemplo, comparar una gráfica de distancia-tiempo con una ecuación de distancia-tiempo para determinar cuál de dos objetos en movimiento tiene mayor velocidad.

nuestra traducción · texto original (EN): Graph proportional relationships, interpreting the unit rate as the slope of the graph. Compare two different proportional relationships represented in different ways. For example, compare a distance-time graph to a distance-time equation to determine which of two moving objects has greater speed.

CCSS Mathematics (2010), Grade 8, Expressions and Equations, standard 8.EE.B.5

Finding Slope and y-Intercept of a Line (en nuestro curso 8)
Punto del currículo 8.EE.B.6 · Contenidos de enseñanza · verificado con el texto oficial

Usar triángulos semejantes para explicar por qué la pendiente m es la misma entre dos puntos distintos cualesquiera en una recta no vertical en el plano de coordenadas; deducir la ecuación y = mx para una recta que pasa por el origen y la ecuación y = mx + b para una recta que interseca el eje vertical en b.

nuestra traducción · texto original (EN): Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line in the coordinate plane; derive the equation y = mx for a line through the origin and the equation y = mx + b for a line intercepting the vertical axis at b.

CCSS Mathematics (2010), Grade 8, Expressions and Equations, standard 8.EE.B.6

Finding Slope and y-Intercept of a Line (en nuestro curso 8)
Punto del currículo 8.EE.C.7 · Contenidos de enseñanza · verificado con el texto oficial

Resolver ecuaciones lineales con una variable. a. Dar ejemplos de ecuaciones lineales con una variable con una solución, infinitas soluciones o ninguna solución. Mostrar cuál de estas posibilidades es el caso transformando sucesivamente la ecuación dada en formas más simples, hasta que resulte una ecuación equivalente de la forma x = a, a = a, o a = b (donde a y b son números diferentes). b. Resolver ecuaciones lineales con coeficientes de números racionales, incluyendo ecuaciones cuyas soluciones requieran desarrollar expresiones usando la propiedad distributiva y agrupar términos semejantes.

nuestra traducción · texto original (EN): Solve linear equations in one variable. a. Give examples of linear equations in one variable with one solution, infinitely many solutions, or no solutions. Show which of these possibilities is the case by successively transforming the given equation into simpler forms, until an equivalent equation of the form x = a, a = a, or a = b results (where a and b are different numbers). b. Solve linear equations with rational number coefficients, including equations whose solutions require expanding expressions using the distributive property and collecting like terms.

CCSS Mathematics (2010), Grade 8, Expressions and Equations, standard 8.EE.C.7

Solving Equations with Variables on Both Sides (en nuestro curso 8)
Punto del currículo 8.EE.C.8 · Contenidos de enseñanza · verificado con el texto oficial

Analyze and solve pairs of simultaneous linear equations. a. Understand that solutions to a system of two linear equations in two variables correspond to points of intersection of their graphs, because points of intersection satisfy both equations simultaneously. b. Solve systems of two linear equations in two variables algebraically, and estimate solutions by graphing the equations. Solve simple cases by inspection. For example, 3x + 2y = 5 and 3x + 2y = 6 have no solution because 3x + 2y cannot simultaneously be 5 and 6. c. Solve real-world and mathematical problems leading to two linear equations in two variables. For example, given coordinates for two pairs of points, determine whether the line through the first pair of points intersects the line through the second pair.

CCSS Mathematics (2010), Grade 8, Expressions and Equations, standard 8.EE.C.8

Solving Systems of Two Linear Equations (en nuestro curso 8)
Punto del currículo 8.F · Contenidos de enseñanza · verificado con el texto oficial

Funciones

nuestra traducción · texto original (EN): Functions

CCSS Mathematics (2010), Grade 8, domain Functions (8.F)
Punto del currículo 8.F.A · Contenidos de enseñanza · verificado con el texto oficial

Definir, evaluar y comparar funciones.

nuestra traducción · texto original (EN): Define, evaluate, and compare functions.

CCSS Mathematics (2010), Grade 8, Functions, cluster A
Punto del currículo 8.F.B · Contenidos de enseñanza · verificado con el texto oficial

Usar funciones para modelar relaciones entre cantidades.

nuestra traducción · texto original (EN): Use functions to model relationships between quantities.

CCSS Mathematics (2010), Grade 8, Functions, cluster B
Punto del currículo 8.F.A.1 · Contenidos de enseñanza · verificado con el texto oficial

Understand that a function is a rule that assigns to each input exactly one output. The graph of a function is the set of ordered pairs consisting of an input and the corresponding output.

CCSS Mathematics (2010), Grade 8, Functions, standard 8.F.A.1

Evaluating a Linear Function (en nuestro curso 8) · Testing if a Point Lies on a Linear Graph (en nuestro curso 8)
Punto del currículo 8.F.A.2 · Contenidos de enseñanza · verificado con el texto oficial

Compare properties of two functions each represented in a different way (algebraically, graphically, numerically in tables, or by verbal descriptions). For example, given a linear function represented by a table of values and a linear function represented by an algebraic expression, determine which function has the greater rate of change.

CCSS Mathematics (2010), Grade 8, Functions, standard 8.F.A.2
Punto del currículo 8.F.A.3 · Contenidos de enseñanza · verificado con el texto oficial

Interpretar la ecuación y = mx + b como la definición de una función lineal, cuya gráfica es una línea recta; dar ejemplos de funciones que no son lineales. Por ejemplo, la función A = s2 que da el área de un cuadrado en función de la longitud de su lado no es lineal porque su gráfica contiene los puntos (1,1), (2,4) y (3,9), que no están en una línea recta.

nuestra traducción · texto original (EN): Interpret the equation y = mx + b as defining a linear function, whose graph is a straight line; give examples of functions that are not linear. For example, the function A = s2 giving the area of a square as a function of its side length is not linear because its graph contains the points (1,1), (2,4) and (3,9), which are not on a straight line.

CCSS Mathematics (2010), Grade 8, Functions, standard 8.F.A.3

Evaluating a Linear Function (en nuestro curso 8)
Punto del currículo 8.F.B.4 · Contenidos de enseñanza · verificado con el texto oficial

Construct a function to model a linear relationship between two quantities. Determine the rate of change and initial value of the function from a description of a relationship or from two ( x, y) values, including reading these from a table or from a graph. Interpret the rate of change and initial value of a linear function in terms of the situation it models, and in terms of its graph or a table of values.

CCSS Mathematics (2010), Grade 8, Functions, standard 8.F.B.4

Finding Slope and y-Intercept of a Line (en nuestro curso 8)
Punto del currículo 8.F.B.5 · Contenidos de enseñanza · verificado con el texto oficial

Describir cualitativamente la relación funcional entre dos cantidades analizando una gráfica (por ejemplo, dónde la función es creciente o decreciente, lineal o no lineal). Esbozar una gráfica que muestre las características cualitativas de una función que ha sido descrita verbalmente.

nuestra traducción · texto original (EN): Describe qualitatively the functional relationship between two quantities by analyzing a graph (e.g., where the function is increasing or decreasing, linear or nonlinear). Sketch a graph that exhibits the qualitative features of a function that has been described verbally.

CCSS Mathematics (2010), Grade 8, Functions, standard 8.F.B.5
Punto del currículo 8.G · Contenidos de enseñanza · verificado con el texto oficial

Geometría

nuestra traducción · texto original (EN): Geometry

CCSS Mathematics (2010), Grade 8, domain Geometry (8.G)
Punto del currículo 8.G.A · Contenidos de enseñanza · verificado con el texto oficial

Understand congruence and similarity using physical models, transparen-cies, or geometry software.

CCSS Mathematics (2010), Grade 8, Geometry, cluster A
Punto del currículo 8.G.B · Contenidos de enseñanza · verificado con el texto oficial

Comprender y aplicar el teorema de Pitágoras.

nuestra traducción · texto original (EN): Understand and apply the Pythagorean Theorem.

CCSS Mathematics (2010), Grade 8, Geometry, cluster B
Punto del currículo 8.G.C · Contenidos de enseñanza · verificado con el texto oficial

Resolver problemas del mundo real y matemáticos que involucran el volumen de cilindros, conos y esferas.

nuestra traducción · texto original (EN): Solve real-world and mathematical problems involving volume of cylinders, cones, and spheres.

CCSS Mathematics (2010), Grade 8, Geometry, cluster C
Punto del currículo 8.G.A.1 · Contenidos de enseñanza · verificado con el texto oficial

Verificar experimentalmente las propiedades de las rotaciones, reflexiones y traslaciones: a. Las rectas se transforman en rectas, y los segmentos de recta en segmentos de recta de la misma longitud. b. Los ángulos se transforman en ángulos de la misma medida. c. Las rectas paralelas se transforman en rectas paralelas.

nuestra traducción · texto original (EN): Verify experimentally the properties of rotations, reflections, and translations: a. Lines are taken to lines, and line segments to line segments of the same length. b. Angles are taken to angles of the same measure. c. Parallel lines are taken to parallel lines.

CCSS Mathematics (2010), Grade 8, Geometry, standard 8.G.A.1
Punto del currículo 8.G.A.2 · Contenidos de enseñanza · verificado con el texto oficial

Understand that a two-dimensional figure is congruent to another if the second can be obtained from the first by a sequence of rotations, reflections, and translations; given two congruent figures, describe a sequence that exhibits the congruence between them.

CCSS Mathematics (2010), Grade 8, Geometry, standard 8.G.A.2
Punto del currículo 8.G.A.3 · Contenidos de enseñanza · verificado con el texto oficial

Describir el efecto de las dilataciones, traslaciones, rotaciones y reflexiones sobre figuras bidimensionales utilizando coordenadas.

nuestra traducción · texto original (EN): Describe the effect of dilations, translations, rotations, and reflections on two-dimensional figures using coordinates.

CCSS Mathematics (2010), Grade 8, Geometry, standard 8.G.A.3
Punto del currículo 8.G.A.4 · Contenidos de enseñanza · verificado con el texto oficial

Comprender que una figura bidimensional es semejante a otra si la segunda se puede obtener a partir de la primera mediante una secuencia de rotaciones, reflexiones, traslaciones y dilataciones; dadas dos figuras bidimensionales semejantes, describir una secuencia que demuestre la semejanza entre ellas.

nuestra traducción · texto original (EN): Understand that a two-dimensional figure is similar to another if the second can be obtained from the first by a sequence of rotations, reflections, translations, and dilations; given two similar two-dimensional figures, describe a sequence that exhibits the similarity between them.

CCSS Mathematics (2010), Grade 8, Geometry, standard 8.G.A.4
Punto del currículo 8.G.A.5 · Contenidos de enseñanza · verificado con el texto oficial

Usar argumentos informales para establecer hechos sobre la suma de los ángulos y el ángulo exterior de triángulos, sobre los ángulos creados cuando rectas paralelas son cortadas por una transversal, y el criterio ángulo-ángulo para la semejanza de triángulos. Por ejemplo, organizar tres copias del mismo triángulo de modo que la suma de los tres ángulos parezca formar una línea, y dar un argumento en términos de transversales sobre por qué esto es así.

nuestra traducción · texto original (EN): Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. For example, arrange three copies of the same triangle so that the sum of the three angles appears to form a line, and give an argument in terms of transversals why this is so.

CCSS Mathematics (2010), Grade 8, Geometry, standard 8.G.A.5

Finding Missing Angles in Triangles and Quadrilaterals (en nuestro curso 8)
Punto del currículo 8.G.B.6 · Contenidos de enseñanza · verificado con el texto oficial

Explain a proof of the Pythagorean Theorem and its converse.

CCSS Mathematics (2010), Grade 8, Geometry, standard 8.G.B.6

Using the Pythagorean Theorem to Find Missing Sides (en nuestro curso 8)
Punto del currículo 8.G.B.7 · Contenidos de enseñanza · verificado con el texto oficial

Aplicar el teorema de Pitágoras para determinar las longitudes de lados desconocidos en triángulos rectángulos en problemas del mundo real y matemáticos en dos y tres dimensiones.

nuestra traducción · texto original (EN): Apply the Pythagorean Theorem to determine unknown side lengths in right triangles in real-world and mathematical problems in two and three dimensions.

CCSS Mathematics (2010), Grade 8, Geometry, standard 8.G.B.7

Using the Pythagorean Theorem to Find Missing Sides (en nuestro curso 8)
Punto del currículo 8.G.B.8 · Contenidos de enseñanza · verificado con el texto oficial

Aplicar el teorema de Pitágoras para encontrar la distancia entre dos puntos en un sistema de coordenadas.

nuestra traducción · texto original (EN): Apply the Pythagorean Theorem to find the distance between two points in a coordinate system.

CCSS Mathematics (2010), Grade 8, Geometry, standard 8.G.B.8
Punto del currículo 8.G.C.9 · Contenidos de enseñanza · verificado con el texto oficial

Conocer las fórmulas para los volúmenes de conos, cilindros y esferas y usarlas para resolver problemas del mundo real y matemáticos.

nuestra traducción · texto original (EN): Know the formulas for the volumes of cones, cylinders, and spheres and use them to solve real-world and mathematical problems.

CCSS Mathematics (2010), Grade 8, Geometry, standard 8.G.C.9

Finding the Volume of Cylinders, Cones, and Spheres (en nuestro curso 8)
Punto del currículo 8.SP · Contenidos de enseñanza · verificado con el texto oficial

Estadística y Probabilidad

nuestra traducción · texto original (EN): Statistics and Probability

CCSS Mathematics (2010), Grade 8, domain Statistics and Probability (8.SP)
Punto del currículo 8.SP.A · Contenidos de enseñanza · verificado con el texto oficial

Investigar patrones de asociación en datos bivariados.

nuestra traducción · texto original (EN): Investigate patterns of association in bivariate data.

CCSS Mathematics (2010), Grade 8, Statistics and Probability, cluster A
Punto del currículo 8.SP.A.1 · Contenidos de enseñanza · verificado con el texto oficial

Construir e interpretar diagramas de dispersión para datos de medición bivariados para investigar patrones de asociación entre dos cantidades. Describir patrones tales como agrupaciones, valores atípicos, asociación positiva o negativa, asociación lineal y asociación no lineal.

nuestra traducción · texto original (EN): Construct and interpret scatter plots for bivariate measurement data to investigate patterns of association between two quantities. Describe patterns such as clustering, outliers, positive or negative association, linear association, and nonlinear association.

CCSS Mathematics (2010), Grade 8, Statistics and Probability, standard 8.SP.A.1
Punto del currículo 8.SP.A.2 · Contenidos de enseñanza · verificado con el texto oficial

Saber que las líneas rectas se utilizan ampliamente para modelar relaciones entre dos variables cuantitativas. Para los diagramas de dispersión que sugieren una asociación lineal, ajustar de manera informal una línea recta y evaluar de manera informal el ajuste del modelo juzgando la cercanía de los puntos de datos a la línea.

nuestra traducción · texto original (EN): Know that straight lines are widely used to model relationships between two quantitative variables. For scatter plots that suggest a linear association, informally fit a straight line, and informally assess the model fit by judging the closeness of the data points to the line.

CCSS Mathematics (2010), Grade 8, Statistics and Probability, standard 8.SP.A.2
Punto del currículo 8.SP.A.3 · Contenidos de enseñanza · verificado con el texto oficial

Usar la ecuación de un modelo lineal para resolver problemas en el contexto de datos de medición bivariados, interpretando la pendiente y el intercepto. Por ejemplo, en un modelo lineal para un experimento de biología, interpretar una pendiente de 1.5 cm/hr en el sentido de que una hora adicional de luz solar al día se asocia con 1.5 cm adicionales en la altura de la planta madura.

nuestra traducción · texto original (EN): Use the equation of a linear model to solve problems in the context of bivariate measurement data, interpreting the slope and intercept. For example, in a linear model for a biology experiment, interpret a slope of 1.5 cm/hr as meaning that an additional hour of sunlight each day is associated with an additional 1.5 cm in mature plant height.

CCSS Mathematics (2010), Grade 8, Statistics and Probability, standard 8.SP.A.3
Punto del currículo 8.SP.A.4 · Contenidos de enseñanza · verificado con el texto oficial

Comprender que los patrones de asociación también se pueden observar en datos categóricos bivariados al mostrar frecuencias y frecuencias relativas en una tabla de doble entrada. Construir e interpretar una tabla de doble entrada que resuma datos sobre dos variables categóricas recopilados de los mismos sujetos. Usar frecuencias relativas calculadas para filas o columnas para describir una posible asociación entre las dos variables. Por ejemplo, recopilar datos de los estudiantes de su clase sobre si tienen o no una hora límite en noches de días de escuela y si tienen o no tareas asignadas en casa. ¿Existe evidencia de que aquellos que tienen una hora límite también tienden a tener tareas?

nuestra traducción · texto original (EN): Understand that patterns of association can also be seen in bivariate categorical data by displaying frequencies and relative frequencies in a two-way table. Construct and interpret a two-way table summarizing data on two categorical variables collected from the same subjects. Use relative frequencies calculated for rows or columns to describe possible association between the two variables. For example, collect data from students in your class on whether or not they have a curfew on school nights and whether or not they have assigned chores at home. Is there evidence that those who have a curfew also tend to have chores?

CCSS Mathematics (2010), Grade 8, Statistics and Probability, standard 8.SP.A.4

Competencias paso a paso

Using the Pythagorean Theorem to Find Missing Sides

Students learn to use the Pythagorean theorem to calculate missing sides of right triangles and test whether a triangle has a right angle.

Punto del currículo 8.G.B.6 Explain a proof of the Pythagorean Theorem and its converse.
Punto del currículo 8.G.B.7 Aplicar el teorema de Pitágoras para determinar las longitudes de lados desconocidos en triángulos rectángulos en problemas del mundo real y matemáticos en dos y tres dimensiones. (nuestra traducción)

In eighth grade, students use the Pythagorean relationship (a² + b² = c²) to find missing side lengths in right triangles and to test whether a given triangle contains a right angle. They square the known measurements, add or subtract those values, and take square roots to determine the unknown length.

A frequent error happens when solving for a missing leg. Students often add the squares of the two given side lengths automatically, forgetting that finding a leg requires subtracting the known leg's square from the hypotenuse's square. Another common slip is carrying out the arithmetic correctly but forgetting to take the square root at the end, leaving the answer as c² instead of c.

Practice tasks provide triangle diagrams or lists of three side measurements. Exercises typically take three forms: Find the hypotenuse when both legs are provided, Find a leg of a right triangle when the hypotenuse and one leg are known, and Is the triangle right-angled? where students substitute three side lengths into the formula to check if the equation holds true.

Crear una hoja de esta habilidad

Tipos de ejercicios: Calcula la hipotenusa · Calcula un cateto · ¿Es rectángulo el triángulo?

Finding the Volume of Cylinders, Cones, and Spheres

Students learn to recall formulas and calculate the volume of cylinders, cones, and spheres to solve mathematical and real-world problems.

Punto del currículo 8.G.C.9 Conocer las fórmulas para los volúmenes de conos, cilindros y esferas y usarlas para resolver problemas del mundo real y matemáticos. (nuestra traducción)

In eighth grade, students learn to know and apply the volume formulas for three curved three-dimensional shapes: cylinders, cones, and spheres. They identify given measurements such as radius, diameter, or height, apply exponents by squaring or cubing values, and use multiplication with pi to find total volume.

A common mistake is mixing up radius and diameter, leading students to square or cube the full width across the shape instead of half of it. Another frequent error is confusing the powers and fractional coefficients across shapes—such as squaring the radius instead of cubing it for a sphere, or forgetting to multiply by 1/3 for a cone or 4/3 for a sphere.

Tasks on printable worksheets are organized around three focused formats: Volume of a cylinder, Volume of a cone, and Volume of a sphere. Students work from geometric diagrams or word problems displaying measurements to compute the correct volume for each solid.

Crear una hoja de esta habilidad

Tipos de ejercicios: Volumen de la esfera · Volumen del cilindro · Volumen del cono

Finding Slope and y-Intercept of a Line

Students learn to determine the slope and y-intercept of a linear function by reading coordinate graphs and calculating the rate of change between two points.

Punto del currículo 8.EE.B.5 Representar gráficamente relaciones proporcionales, interpretando la tasa unitaria como la pendiente de la gráfica. Comparar dos relaciones proporcionales diferentes representadas de maneras distintas. Por ejemplo, comparar una gráfica de distancia-tiempo con una ecuación de distancia-tiempo para determinar cuál de dos objetos en movimiento tiene mayor velocidad. (nuestra traducción)
Punto del currículo 8.EE.B.6 Usar triángulos semejantes para explicar por qué la pendiente m es la misma entre dos puntos distintos cualesquiera en una recta no vertical en el plano de coordenadas; deducir la ecuación y = mx para una recta que pasa por el origen y la ecuación y = mx + b para una recta que interseca el eje vertical en b. (nuestra traducción)
Punto del currículo 8.F.B.4 Construct a function to model a linear relationship between two quantities. Determine the rate of change and initial value of the function from a description of a relationship or from two ( x, y) values, including reading these from a table or from a graph. Interpret the rate of change and initial value of a linear function in terms of the situation it models, and in terms of its graph or a table of values.

In 8th grade, students connect linear relationships to lines on a coordinate plane. They identify the slope as the constant rate of change (vertical change divided by horizontal change) and locate the y-intercept, which is the initial value where the line crosses the vertical axis, forming the equation y = mx + b. Students work with lines passing through the origin as well as lines shifted along the vertical axis.

A frequent error occurs when students invert the slope formula, dividing the change in x by the change in y instead of rise over run. When calculating slope from two coordinates, students also tend to mix up the order of subtraction, subtracting the second x-value from the first while doing the opposite for the y-values. Another common mistake is identifying the horizontal intercept instead of the vertical y-intercept on a grid.

Practice tasks focus directly on these visual and numeric skills using three main formats:

Finding the y-intercept from a graph by identifying the coordinate where a line crosses the vertical axis.
Calculating the slope from a graph by counting the rise and run between grid intersections.
Finding the slope through two points by calculating the change in y over the change in x from two given (x, y) coordinate pairs.

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Tipos de ejercicios: Ordenada en el origen a partir de la gráfica · Pendiente a partir de la gráfica · Pendiente de la recta por dos puntos

Finding Square Roots and Cube Roots

Students learn to evaluate square roots of small perfect squares and cube roots of small perfect cubes using root symbols.

Punto del currículo 8.EE.A.2 Use square root and cube root symbols to represent solutions to equations of the form x2 = p and x3 = p, where p is a positive rational number. Evaluate square roots of small perfect squares and cube roots of small perfect cubes. Know that √2 is irrational.

In this grade, students work with the square root symbol and cube root symbol to solve equations and evaluate numerical expressions. They focus on finding the exact values of small perfect squares (such as finding that the square root of 64 is 8) and small perfect cubes (such as finding that the cube root of 27 is 3).

A common error is confusing roots with division. Because students see a 2 implied in square roots and a 3 in cube roots, they often divide the given number by 2 or 3 instead of finding the factor that multiplies by itself. For instance, a student might mistakenly answer that the square root of 16 is 8, or that the cube root of 27 is 9.

Worksheet tasks give students direct practice with these symbols. Using prompts from Find the square root and Find the cube root, students are presented with expressions like √49 or ∛8 and write down the single whole number that solves each problem.

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Tipos de ejercicios: Calcula la raíz cuadrada · Calcula la raíz cúbica

Finding Missing Angles in Triangles and Quadrilaterals

Students find an unknown angle in a triangle or quadrilateral by subtracting known angles from 180 or 360 degrees.

Punto del currículo 8.G.A.5 Usar argumentos informales para establecer hechos sobre la suma de los ángulos y el ángulo exterior de triángulos, sobre los ángulos creados cuando rectas paralelas son cortadas por una transversal, y el criterio ángulo-ángulo para la semejanza de triángulos. Por ejemplo, organizar tres copias del mismo triángulo de modo que la suma de los tres ángulos parezca formar una línea, y dar un argumento en términos de transversales sobre por qué esto es así. (nuestra traducción)

Students use the foundational geometric facts that the interior angles of a triangle add up to 180 degrees and the interior angles of a quadrilateral add up to 360 degrees. To find an unknown angle, they add the given angle measures and subtract that combined total from either 180 or 360 degrees.

A frequent error is mixing up the two target totals, such as attempting to subtract three angles of a four-sided shape from 180 degrees instead of 360 degrees. Arithmetic slips also occur during the multi-step addition when summing the known values before the final subtraction.

In practice, tasks come from two core templates: The third angle of a triangle, where two angle measures are provided and students solve for the remaining one, and The fourth angle of a quadrilateral, where students are given three angle values and calculate the final missing angle.

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Tipos de ejercicios: El cuarto ángulo del cuadrilátero · El tercer ángulo del triángulo

Evaluating Powers of Integers and Fractions

Students learn to calculate the exact numerical value of integers and fractions raised to positive and negative integer exponents.

Punto del currículo 8.EE.A.1 Know and apply the properties of integer exponents to generate equivalent numerical expressions. For example, 32 × 3 –5 = 3–3 = 1/33 = 1/27.

At this stage, students compute the numerical values of expressions where integers or fractions are raised to integer powers. They apply rules for positive and negative exponents to turn expressions like 3 with an exponent of -3 into fractional values such as 1/27.

A common mistake is treating a negative exponent as a negative sign for the final answer, leading students to write -27 instead of 1/27. Students also frequently multiply the base by the exponent instead of multiplying the base by itself.

In practice, students work on two specific task types:

Evaluate a power of an integer, calculating the resulting whole number or fraction from an integer base.
Evaluate a power of a fraction, calculating the result when a fraction is raised to an exponent.

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Tipos de ejercicios: Calcula la potencia de un entero · Calcula la potencia de una fracción

Understanding Negative Exponents

Students learn to rewrite numerical expressions with negative integer exponents as fractions and calculate their values.

Punto del currículo 8.EE.A.1 Know and apply the properties of integer exponents to generate equivalent numerical expressions. For example, 32 × 3 –5 = 3–3 = 1/33 = 1/27.

In eighth grade, students learn to interpret negative integer exponents to create equivalent numerical expressions. They discover that raising a number to a negative power produces a reciprocal rather than a negative value, allowing them to rewrite terms like 3^-3 into 1/3^3 and evaluate the result as 1/27.

A common mistake is treating the negative exponent as a negative sign for the base. Students often multiply the base by the exponent to get -9, or compute the power normally and stick a negative sign in front to get -27. This happens because learners associate the minus symbol strictly with negative quantities rather than repeated division.

Practice tasks based on the Negative exponent template give students expressions with negative integer powers and ask them to rewrite each term using positive exponents or evaluate it to a fraction.

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Using Rules of Integer Exponents

Students learn to apply the properties of integer exponents to simplify and write equivalent numerical expressions, including those with negative powers.

Punto del currículo 8.EE.A.1 Know and apply the properties of integer exponents to generate equivalent numerical expressions. For example, 32 × 3 –5 = 3–3 = 1/33 = 1/27.

Eighth graders apply properties of integer exponents to generate equivalent numerical expressions. Working with positive integers, zero, and negative integers as exponents, students combine powers with the same base—for example, simplifying 3 to the 2nd power multiplied by 3 to the -5th power into 3 to the -3rd power, or 1/27.

A common hurdle is confusing negative exponents with negative values. Students often mistakenly calculate 3 to the -3rd power as -27 or -9 instead of recognizing that the negative exponent creates a fraction, 1/27. Another frequent slip is multiplying the base numbers together rather than keeping the base unchanged while combining the powers.

Practice exercises often appear as missing exponent tasks. Given an incomplete equation governed by exponent rules, students determine the missing integer power needed to make both sides of the numerical expression equal.

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Estimating Square Roots

Students learn to approximate the value of square roots by finding the consecutive whole numbers and decimals they fall between.

Punto del currículo 8.NS.A.2 Use rational approximations of irrational numbers to compare the size of irrational numbers, locate them approximately on a number line diagram, and estimate the value of expressions (e.g., π 2). For example, by truncating the decimal expansion of √2, show that √2 is between 1 and 2, then between 1.4 and 1.5, and explain how to continue on to get better approximations.

Students learn to find rational approximations for non-perfect square roots by placing them between known benchmark values. Using nearby perfect squares, they determine that an irrational root like √2 falls between the integers 1 and 2 (since 1² = 1 and 2² = 4). They can then narrow that window further to show it sits between 1.4 and 1.5, establishing a step-by-step way to get closer approximations.

A common mistake occurs when students confuse finding a square root with dividing by 2. When asked to estimate an unfamiliar value like √20, a student might mistakenly guess 10 rather than recognizing that √20 lies between 4 and 5 because 4² is 16 and 5² is 25.

Worksheets using the Estimate a square root task present students with non-perfect square roots and ask them to identify the consecutive whole numbers that frame each root, or to approximate where the value falls on a number line.

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Working with Scientific Notation

Students learn to write, compare, and calculate with very large and very small numbers expressed as a number times an integer power of 10.

Punto del currículo 8.EE.A.3 Usar números expresados en forma de un solo dígito multiplicado por una potencia entera de 10 para estimar cantidades muy grandes o muy pequeñas, y para expresar cuántas veces mayor es una que la otra. Por ejemplo, estimar la población de los Estados Unidos como 3 × 10 8 y la población del mundo como 7 × 10 9, y determinar que la población mundial es más de 20 veces mayor. (nuestra traducción)
Punto del currículo 8.EE.A.4 Perform operations with numbers expressed in scientific notation, including problems where both decimal and scientific notation are used. Use scientific notation and choose units of appropriate size for measurements of very large or very small quantities (e.g., use millimeters per year for seafloor spreading). Interpret scientific notation that has been generated by technology.

Students work with quantities written in the form of a single digit times an integer power of 10, such as 3 × 10⁸ or 7 × 10⁹, to handle very large or tiny measurements. They learn to compare these numbers to see how many times larger one is than another, perform basic operations with numbers in scientific notation, and work between standard decimal form and powers of 10.

A common mistake occurs when students add or multiply and forget to adjust the final expression back into proper form. For example, after multiplying, they might leave an answer as 15 × 10⁴ rather than shifting the decimal to write 1.5 × 10⁵. Students also frequently confuse the direction of the decimal point when dealing with negative exponents, mistakenly treating negative powers as negative values rather than very small fractions.

In the Scientific notation tasks, students practice converting values between decimal form and scientific notation, comparing quantities with different powers of 10, and computing products or quotients involving measurements from science and technology.

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Solving Equations with Variables on Both Sides

Students learn to solve linear equations that have variables on both sides, using the distributive property, combining like terms, and working with rational numbers.

Punto del currículo 8.EE.C.7 Resolver ecuaciones lineales con una variable. a. Dar ejemplos de ecuaciones lineales con una variable con una solución, infinitas soluciones o ninguna solución. Mostrar cuál de estas posibilidades es el caso transformando sucesivamente la ecuación dada en formas más simples, hasta que resulte una ecuación equivalente de la forma x = a, a = a, o a = b (donde a y b son números diferentes). b. Resolver ecuaciones lineales con coeficientes de números racionales, incluyendo ecuaciones cuyas soluciones requieran desarrollar expresiones usando la propiedad distributiva y agrupar términos semejantes. (nuestra traducción)

Eighth graders learn to solve linear equations where the unknown appears on both sides of the equals sign. They work with rational number coefficients—including integers, fractions, and decimals—by using the distributive property to expand expressions and collecting like terms on each side. By transforming equations step by step, students find whether an equation leads to a single solution (x = a), no solution (a false statement like a = b), or infinitely many solutions (a true statement like a = a).

A frequent error occurs when rearranging terms across the equals sign. Students often forget to use inverse operations, adding a term to both sides instead of subtracting it, particularly when negative coefficients are involved. Another difficulty arises when the variable cancels out entirely: students may mistakenly think the answer is zero rather than interpreting the resulting numbers to decide if the equation has no solution or infinitely many solutions.

Tasks built from the Unknown on both sides template present linear equations such as 4(x − 2) = 2x + 10 or expressions involving fractions. Students show their work line by line, simplifying each side, collecting the variable terms onto one side, and stating the final solution.

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Solving Systems of Two Linear Equations

Students learn to solve pairs of linear equations algebraically, find their intersection points on a graph, and recognize when two equations have no shared solution.

Punto del currículo 8.EE.C.8 Analyze and solve pairs of simultaneous linear equations. a. Understand that solutions to a system of two linear equations in two variables correspond to points of intersection of their graphs, because points of intersection satisfy both equations simultaneously. b. Solve systems of two linear equations in two variables algebraically, and estimate solutions by graphing the equations. Solve simple cases by inspection. For example, 3x + 2y = 5 and 3x + 2y = 6 have no solution because 3x + 2y cannot simultaneously be 5 and 6. c. Solve real-world and mathematical problems leading to two linear equations in two variables. For example, given coordinates for two pairs of points, determine whether the line through the first pair of points intersects the line through the second pair.

In 8th grade, students learn to find the values for two variables that make two separate linear equations true at the same time. They connect algebra to geometry by understanding that the solution to a system corresponds to the point of intersection where their graphs meet. Students estimate solutions by graphing lines, calculate exact solutions algebraically, and inspect simple cases directly—such as identifying that lines like 3x + 2y = 5 and 3x + 2y = 6 share no common solution because parallel lines never cross.

A common mistake is stopping halfway: students often calculate the correct value for one variable, such as x, and forget to substitute it back to find y. Another frequent stumbling block is confusing a system that has no solution with one where the answer is zero; students may struggle to recognize that when two equations contradict each other, no coordinate pair can satisfy both.

In a standard System of two equations task, students are presented with two linear equations written with two variables. They solve the system by calculating the coordinates where the lines intersect, estimating the intersection point from a coordinate plane, or identifying whether the pair has a single solution, infinitely many solutions, or no solution at all.

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Evaluating a Linear Function

Students substitute an input value into a linear equation in the form y = mx + b to calculate the corresponding output value.

Punto del currículo 8.F.A.1 Understand that a function is a rule that assigns to each input exactly one output. The graph of a function is the set of ordered pairs consisting of an input and the corresponding output.
Punto del currículo 8.F.A.3 Interpretar la ecuación y = mx + b como la definición de una función lineal, cuya gráfica es una línea recta; dar ejemplos de funciones que no son lineales. Por ejemplo, la función A = s2 que da el área de un cuadrado en función de la longitud de su lado no es lineal porque su gráfica contiene los puntos (1,1), (2,4) y (3,9), que no están en una línea recta. (nuestra traducción)

Eighth graders learn that a linear function written in the form y = mx + b is a rule linking each input (x) to exactly one output (y). Students plug a given input number into the equation and carry out the multiplication and addition to calculate the output, forming an ordered pair (x, y) that lies on the line.

A frequent error happens when working with negative numbers or following the order of operations. When evaluating an expression like y = -2x + 7 with a negative input, students often forget that multiplying two negative numbers yields a positive result, or they may accidentally add before multiplying by the slope.

In an Evaluate a linear function worksheet, students are typically presented with a rule such as y = 3x - 5 and asked to find the value of y when given a specific value for x, such as x = 4 or x = -3.

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Testing if a Point Lies on a Linear Graph

Students learn to determine whether an ordered pair lies on a function's graph by checking if the input value yields the matching output value.

In 8th grade, students learn that the graph of a function consists of all the ordered pairs where each input is matched with its output. To test whether a specific point belongs on the line, students take the coordinate pair, substitute the input value into the function's equation, and calculate whether it produces the stated output value.

A frequent error occurs when students swap the coordinates, plugging the y-value in place of x. This mix-up often leads them to evaluate the wrong arithmetic expression and incorrectly claim that an off-line point sits on the graph.

Worksheet tasks built around the Is the point on the graph? template provide a linear rule along with a coordinate pair. Students calculate the rule's value for the given input and answer with a clear "yes" or "no" based on whether the result equals the second coordinate.

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Potencia de exponente negativo