Grasp Maths

Year 3

Compare and order unit fractions, and fractions with the same denominators

Compare the size of unit fractions and fractions with the same denominator.

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Lesson overview

Number - fractions

For unit fractions, the larger the denominator, the smaller the fraction part. For fractions with the same denominator, the larger numerator shows more of the same-sized parts.

Compare unit fractions

13\frac{1}{3} is greater than 14\frac{1}{4} because thirds are larger parts than quarters.

Fewer equal parts means each part is bigger.

Compare same denominators

58\frac{5}{8} is greater than 38\frac{3}{8} because both fractions are eighths and 5 parts are more than 3 parts.

When the denominator matches, compare the numerators.

Order fractions

15\frac{1}{5}, 25\frac{2}{5} and 45\frac{4}{5} can be ordered from smallest to largest.

The order depends on the numerator when the denominator is the same.

Worked example

Which is greater: 16\frac{1}{6} or 13\frac{1}{3}?

  1. Both fractions are unit fractions.
  2. Sixths split the whole into more parts than thirds.
  3. More parts means smaller pieces.
  4. So 13\frac{1}{3} is greater than 16\frac{1}{6}.

Try it

Decide whether you are comparing unit fractions or fractions with the same denominator first.

Question 1

Which is greater?

Question 2

Which is greater?

Question 3

Which order is from smallest to largest?

Question 4

Which numerator makes a larger fraction in __/8 compared with 38\frac{3}{8}?

Question 5

Which statement is true?

Common mistakes

Watch for these when working through the lesson.

  • Thinking a larger denominator means a larger unit fraction.
  • Comparing denominators when the denominators are already the same.
  • Ordering fractions by the numerator only in every situation.

Related topics

These ideas fit closely with this lesson.

  • Recognise and use fractions as numbers: unit fractions and non-unit fractions with small denominators.
  • Recognise and show, using diagrams, equivalent fractions with small denominators.

Practice next

Independent practice will plug in here

This lesson introduces the idea clearly first. Deeper adaptive practice can sit here later.