Comparing fractions
Compare and order unit fractions, and fractions with the same denominator
What a learner can do afterwards
- Order 1/2, 1/3, 1/4, 1/5 from largest to smallest
- Explain that a larger denominator means smaller unit fractions
- Compare 2/5 and 4/5 and explain that 4/5 is larger because it has more fifths
The lesson
You already know how to split a shape into equal parts, and how fractions sit on a number line. Comparing fractions means figuring out which one is bigger. If two fractions have the same bottom number, called the denominator, the pieces are the same size. Then you just compare the top numbers. More on top means a bigger fraction.
Ben ate 3/8 of a cake. His sister ate 5/8 of the same cake. Both cakes were cut into 8 same-size slices, so just compare the top numbers. 5 is more than 3, so his sister ate more.
Quick rule: if the denominators match, compare the top numbers, more is bigger. If the top number is 1 for both, like with 1/2, 1/3, 1/4, 1/5, the fraction with the smaller denominator is the bigger piece.
Same denominator: compare the top numbers. Unit fractions: the bigger the denominator, the smaller the piece.
Watch it
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.