Children learn to understand fractions with denominators 2, 3, 4, 6, and 8 as numbers built from equal parts, locating them on number lines and identifying them in sets.
In third grade, children learn that a fraction is an exact number representing equal parts of a whole. Working with denominators limited to 2, 3, 4, 6, and 8, they learn that a unit fraction such as 1/4 is one equal piece of a whole, while a fraction such as 3/4 represents three of those 1/4 pieces. They apply this on a number line from 0 to 1, dividing the space into equal intervals to locate fractions as precise points.
A frequent error occurs when children treat the numerator and denominator as separate, unrelated whole numbers rather than a single value. This often leads them to think that 1/8 must be larger than 1/4 simply because 8 is greater than 4, missing the concept that dividing a whole into more parts makes each individual part smaller. Children may also count divided sections without checking whether the parts are equal in size.
Practice tasks reinforce these ideas using visual models. In a fraction of a set: a/b of the whole task, a child sees a group of items—such as 8 stars divided evenly into parts—and identifies what fraction is shaded or circled, writing a/b (such as 3/8 or 5/8) to name that portion of the whole group.