Matemáticas de 1.º de Primaria

In Year 1, pupils learn to read and write mathematical statements using subtraction (–) and equals (=) signs, mastering subtraction within 20. As they build confidence, they extend these skills up to 100. While subtracting two two-digit numbers is formalised by Year 2, Year 1 children explore larger numbers within 100 using visual supports, taking away single digits or tens step by step.

A common difficulty occurs when counting backwards across a tens boundary. For example, when subtracting from 52, a child might mistakenly jump to 51 and then land on 50 or 39 rather than 49. Another typical error is counting the starting number as the first step on a grid rather than counting the jumps between numbers, which leaves the final answer one number too high.

Task worksheets give children concrete practice using varied formats. Typical activities include jumping back on the hundred grid, completing two subtractions in a row, or solving multi-step scenarios where some items leave and others arrive. Children also build reasoning skills by checking a given calculation to find and correct a mistake, or working backwards to discover how many items were there at the start.

Children work with numbers up to 100 to understand which values are larger, smaller, or equal. Using objects, pictorial models, and number lines, they practice key comparison language such as equal to, more than, less than, most, and least, alongside introducing the symbols <, >, and = to show how two values relate.

A common error occurs when children compare two-digit numbers by looking at the ones digit first instead of the tens digit. For example, a child might see 39 and 51 and think 39 is greater simply because 9 is bigger than 5 or 1. Confusing the direction of the < and > symbols is another frequent stumbling block at this stage.

Practice tasks guide children through these comparisons step by step. Typical activities include Insert the sign: <, > or = between two numbers, word problems asking Which group collected the least, and sequencing exercises like Order five numbers from greatest to least or least to greatest.

In Year 1, children learn to recognise different denominations of coins and notes and apply their addition and subtraction facts within 20 to everyday spending. While calculating change with mixed pounds and pence spans the curriculum across Key Stages 1 and 2, Year 1 learners focus on single-unit values up to 20. They combine small coin values to reach a target amount and calculate how much is left after a purchase.

A common mistake at this stage is confusing the physical size or quantity of coins with their actual monetary value. Children often count each coin as "one" regardless of what is stamped on it, mistaking three 1p coins for being worth more than a single 5p coin, or treating a 10p piece as worth 1p when adding up amounts.

Practical worksheet tasks use familiar shop settings to make these values visual. In exercises like Which coins to pay with and Is there enough money, children identify the correct combination of coins needed for a price tag. In tasks such as How much do several items cost and Shopping and change, they add small prices together and calculate how much money is missing or due back.

In Year 1, children learn to recognise and use everyday language for dates, focusing on the days of the week, weeks, months, and years. At this stage, they practice ordering the seven days of the week, finding what day it will be after a few days or what day it was in the past, and counting the days that pass between dates on a calendar.

A common mistake happens when counting how many days pass between two dates. Children often include the starting day itself—counting Tuesday, Wednesday, Thursday, and Friday as four days rather than counting the three days that actually elapsed. Children also stumble when counting across the weekend, forgetting that Sunday cycles back to Monday.

Typical tasks ask children to solve short calendar problems, such as Which day of the week will it be? or What day was it some days ago?. Other worksheets show a calendar view where pupils find How many days between the marked dates, evaluate true-or-false statements about elapsed days, or find and correct a mistake in a counting sequence.

In Year 1, children build an early understanding of time calculations by comparing and sequencing everyday activities. Using words like earlier, later, quicker, and slower, they describe how events relate to one another. At this stage, they also begin exploring the relationship between units of time—learning that there are 60 minutes in an hour—and work out basic intervals and durations using whole hours and half hours.

A common difficulty is confusing earlier and later, leading children to reverse the order of events. Learners also frequently treat time like base-ten numbers, mistakenly assuming there are 100 minutes in an hour rather than 60, which leads to errors when converting hours to minutes or calculating how many minutes have passed.

Worksheet tasks make these relationships concrete using familiar daily routines. In The day plan: put the times in order, children arrange scheduled activities chronologically. Other tasks, such as Time duration (how long?), What time did it start?, and How much longer one lasted than the other, prompt pupils to calculate elapsed intervals or compare the lengths of two events. Children also reinforce basic time facts through tasks like Hours to minutes: choose the correct answer.

In Year 1, children work with addition and subtraction within 20 to solve one-step missing number problems using concrete objects, pictures, and written equations. Rather than always working out the end total, they learn that the equals sign shows equivalence between two sides, solving equations where the unknown appears anywhere, such as 7 = □ – 9.

A typical error occurs when children treat the equals sign simply as a signal to calculate with whatever two numbers they can see. In an equation like 5 + □ = 8 or 7 = □ – 9, a child might add 7 and 9 or subtract 5 from 8 without thinking about the structure of the equation, writing an answer that makes the statement untrue.

Tasks give children structured practice through visual and written formats. Typical activities include missing addend equations, finding the starting number that a value was taken from in subtraction, working out the weight of a hidden block on a balanced scale, and finding a missing number within a sum of three numbers to make both sides equal.

In Year 1, children learn to recognise, find, and name a half as one of two equal parts and a quarter as one of four equal parts. They work concretely with individual shapes, physical objects, and small quantities of items, establishing that each share must be identical in size or amount.

A common error is ignoring whether the parts are equal. Children often divide a shape or a set into two or four uneven sections and still refer to them as halves or quarters simply because they count two or four pieces altogether.

Tasks reinforce this distinction using visual shapes and grouped objects. Worksheets like Part of a whole and How many parts left unshaded: true or false ask children to identify accurately divided shapes, while templates such as Fraction of a set: how many is one part and A fraction of a set: fix the mistake challenge them to find equal shares of a group and spot uneven distributions.

In Year 1, children learn to read, write, and interpret addition statements using the + and = signs, calculating totals up to 20. They add one-digit and two-digit numbers—such as 14 + 3, or adding zero—where the ones digits do not combine to make ten or more, meaning no regrouping into a new ten is needed.

A typical error occurs when children count on from the larger number but accidentally include that starting number in their count. For instance, when calculating 13 + 4, a child may tap four times while saying "13, 14, 15, 16", landing on 16 instead of 17. Other children restart counting from 1 every time because they do not yet trust number bonds within the teen numbers.

Tasks reinforce these steps using structured visuals and varied questions. Children count dots displayed across two ten-frames, identify whether an addition statement is true or false, and choose the correct answer from multiple options. They also practice adding three numbers within 20, finding missing amounts, and spotting and correcting mistakes in completed calculations.

In Year 1, children work with numbers within 20 to discover how addition and subtraction are directly linked. Using their knowledge of number bonds, they see that a calculation like 8 + 5 = 13 also gives related subtraction facts such as 13 - 5 = 8. They begin to use this inverse relationship to switch between adding and taking away to check their answers.

A common mistake occurs when children try to check a subtraction but lose track of which number represents the whole total. For example, when checking whether 14 - 6 = 8 is correct, a child might add the starting total to an answer (computing 14 + 8) or try to subtract again (8 - 6), rather than adding the two smaller parts back together.

Practical tasks help children secure this link through concrete problem-solving:

• deciding if a calculation can be verified by asking: Is the check of the subtraction right?
• reversing a sum directly, such as using addition to check a subtraction by adding;
• spotting and fixing errors using tasks like correct the mistake in checking a subtraction;
• working backwards to solve missing-number questions like what number was it subtracted from?

Children learn to read whole measurements directly from a ruler and explore standard metric units. While early measurement in Year 1 starts with comparing lengths and heights, these activities build towards measuring across primary stages by having children read scales and convert between units, such as changing metres and centimetres into centimetres, or centimetres and millimetres into millimetres.

A common mistake occurs when using a ruler: children often align the item with the start of the plastic edge or the number 1 rather than starting exactly at 0. Children can also get confused by the base units when converting, forgetting that there are 10 millimetres in a centimetre but 100 centimetres in a metre.

Worksheet activities provide direct practice with scales and calculations, including:

• Read the length from the ruler, where children determine where an object ends along a printed scale.
• Converting metres and centimetres to centimetres and converting centimetres and millimetres to millimetres.
• Evaluating statements in centimetres to millimetres: true or false and correcting worked examples in metres and centimetres: fix the mistake.

In Year 1, children solve one-step word problems involving addition and subtraction with numbers up to 20. Using concrete objects and pictorial representations, they act out situations to work out totals or find what remains after some items are taken away. They also begin to work with missing number problems, such as finding an unknown amount they started with.

A common difficulty occurs when children pick out the numbers they see and immediately add them together without understanding the story's action. When a problem asks how many are left or includes an extra number that is not needed, children often combine every figure they encounter because they have not yet identified which operation the situation requires.

Practice tasks present brief illustrated scenarios. Children might be asked to decide which operation solves the problem, calculate how many are left, find how many were there at the start, or filter out an extra number to choose the correct result.

In Year 1, children learn to identify and name common flat shapes: circles, triangles, and rectangles (including squares). At this stage, the focus is on recognising these shapes on sight across different sizes and orientations.

A frequent stumbling block is orientation. When a triangle points downwards or to the side, children often think it is no longer a triangle. Similarly, a square resting on one of its corners is often misidentified as a completely different shape, such as a "diamond", because children rely on the overall silhouette rather than the shape itself.

Practice tasks reinforce recognition through clear visual exercises. Children might be shown a turned figure and asked to choose or write its name, determine whether a label is true or false, correct an incorrect name under a drawing, or count how many triangles they can find hidden inside a larger picture.

In Year 1, children learn to count, read, and write numbers up to 100 in numerals, and numbers from 1 to 20 in both numerals and words. Across Years 1 to 3, this skill expands toward reading and writing numbers up to 1000 in numerals and words.

A common difficulty arises with numbers that have a zero in the middle. Because children often write what they hear spoken aloud, they may record "one hundred and five" as 1005 instead of 105, misunderstanding how zero holds an empty place value column.

Worksheet tasks provide targeted practice to build this accuracy, including:

• Reading the number in words and writing the number in digits.
• Deciding if a given way of writing a number is correct or choosing the correct digits from options.
• Finding the mistake and fixing numbers written with a zero in the middle.

In Year 1, children learn to read analogue clock dials to tell the time to the hour (o’clock) and half past the hour. They learn that the face represents hours and minutes, identifying the shorter hand as the hour hand and the longer hand as the minute hand, and practice drawing hands in the correct positions.

A frequent stumbling block is confusing the two hands or misinterpreting the hour hand when reading half past. For example, at half past four, the hour hand sits halfway between the 4 and the 5. Children often look at the number the hand is approaching and mistakenly read the time as half past five.

Practice tasks present clock dials and ask children to identify which time is shown or decide if a stated time is true or false. Children also identify and correct mistakes on drawn clocks, compare dials to determine which clock shows the earlier time, and count how many minutes remain until the next full hour.

In Year 1, children build an understanding of capacity and volume by working out how much different containers can hold. Using basic counting and their knowledge of halves, children solve practical sharing problems, such as finding how many small bottles a larger jug of juice can fill, or combining half-litre bottles to calculate total litres.

A common mistake occurs when children rely solely on appearance, assuming a taller container always holds more liquid than a shorter, wider one. Pupils also frequently stumble when converting half-litres, counting each bottle as one whole litre instead of recognising that two half-litres make a single litre.

Typical worksheet tasks present clear, illustrated containers. Children might solve problems asking how many bottles will the juice fill, work out how many litres from that many half-litre bottles are shown, or calculate how much more one container holds than the other to find the missing amounts.

In Year 1, children build confidence with numbers up to 100. They practice counting forwards and backwards across 100, starting from zero, one, or any other number. Alongside counting in single steps, they learn to skip-count in multiples of twos, fives, and tens.

A common difficulty occurs when switching direction or crossing tens boundaries. Children often stumble when counting backwards, accidentally skipping numbers or reverting to counting forwards. When skip-counting, they might lose track of the step size—for example, switching from steps of five to steps of ten midway through a sequence.

Practice tasks keep these step patterns clear and engaging. Typical activities include:

• Continuing number tracks by keeping to the same step size forwards or backwards.
• Choosing the next number in a sequence or correcting a misplaced number.
• Working out how many equal jumps it takes to reach a target number.

In Year 1, children learn to compare and describe the sizes of everyday objects using comparative language. For length and height, they identify which item is longer, shorter, or the longest. For mass, they describe items as heavier than or lighter than and practice arranging objects in order from lightest to heaviest.

A frequent stumbling block occurs when comparing lengths that are not aligned at the same starting point. Children often look only at where an item ends, mistakenly picking an object as longer simply because it sits further to one side. When considering mass, young learners also commonly confuse size with weight, assuming that a physically larger object must always be the heavier one.

Worksheet tasks present these concepts visually. Children look at pictures to decide Which one is the longest, arrange a set of items to Put them in order from lightest, or evaluate visual measurements to answer true-or-false and multiple-choice questions asking How much longer is the ribbon.

In Year 1, children learn to identify one more and one less for numbers up to 100. At this stage, they connect counting with the idea that taking one step forward gives a number that is 1 greater (its successor), while taking one step back gives a number that is 1 smaller (its predecessor).

A typical difficulty occurs when crossing decade boundaries, such as finding one less than 30 or one more than 49. Children readily change the ones digit in the middle of a decade, but shifting between tens groups can cause confusion, leading them to give answers like 31 or 39 when asked for one less than 30.

Practice tasks ask pupils to pick which number is 1 greater or which number is 1 smaller for a given value. Children also tackle slightly deeper questions using these neighbours, such as calculating the sum of the successor and the predecessor, deciding if a statement about them is true or false, or choosing the correct answer from a list of options.

In Year 1, children learn to identify and name common 3D shapes, focusing on cuboids (including cubes), pyramids, and spheres. While formal properties such as counting faces, edges, and vertices are introduced as children progress into Year 2, pupils at this stage focus on distinguishing solid shapes by their appearance and recognising them in their environment.

A common hurdle is confusing 2D shape names with 3D solid names. Children often refer to a sphere as a "circle" or a cube as a "square" because they focus on a single flat surface rather than the entire solid. They may also struggle to distinguish between cubes and cuboids before they realise that a cube is a specific type of cuboid with equal square faces.

Practice tasks reinforce correct mathematical vocabulary using clear visual prompts:

• Identifying a shown solid in What is this solid called and Which solid is it? Choose.
• Testing understanding with Which solid is it? True or false and spotting errors in Correct the name of the solid.
• Linking geometric solids to real life in Find an object shaped like the solid, such as matching a sphere to a ball or a cuboid to a tissue box.

In Year 1, children are introduced to the concept of mass and weight. While the national curriculum builds toward measuring and calculating with standard units such as kilograms across Years 1 to 3, children at this level begin by exploring whole kilograms, calculating parts that make up a full unit, and converting between kilograms and decagrams.

A common difficulty arises when working out how much mass is missing to reach a full kilogram. Children often treat the remaining amount as a simple count-up to ten or one hundred without checking the specific conversion rate, miscalculating the amount needed to complete the whole package.

Practice worksheets present these mass concepts through focused visual tasks:

• True or false and multiple-choice questions for converting kilograms to decagrams.
• Direct conversion questions from kilograms into decagrams.
• Exercises determining how much is missing to a full kilogram.
• Practical division-style problems calculating how many portions the package makes.

Children practice identifying and representing quantities by counting items arranged in structured grids and writing down the matching numeral. Working with organised frames helps them move from touching physical objects to interpreting pictorial representations clearly.

A common error is losing the one-to-one match between the spoken number word and the visual item. Children may count faster than their finger points, leading them to skip a counter or count the same one twice as they scan across the rows.

Worksheet activities focus on tasks like Count the counters in the frames. Children view a frame filled with a specific number of counters, count the quantity accurately, and write the correct number in the space provided.