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SATs practice · Year 6Chapter 3 · Fractions
Year 6 Arithmetic (SATs) · Fractions · Lesson 3.3

Year 6 Arithmetic (SATs): Mixed numbers and improper fractions

Part of the Year 6 Arithmetic (SATs) fractions chapter. Chapter overview · whole chapter on one page

3.3

Mixed numbers and improper fractions

Year 6
Recognise mixed numbers and improper fractions, and convert between them (Year 5)
Story. A baker has 4 3/8 kilograms of flour in a sack and wants to put it into bags of 1/8 kilogram. He writes the amount as an improper fraction to count the eighths.

Rule

A mixed number has a whole number and a fraction, such as 2 3/4. An improper fraction has a top number that is bigger than its bottom number, such as 11/4.

To change a mixed number to an improper fraction: multiply the whole number by the bottom, add the top, and keep the bottom. To change back, divide the top by the bottom.

Key ideas

  • 2 3/4 = 11/4, because 2 × 4 + 3 = 11.
  • 17/5 = 3 2/5, because 17 ÷ 5 = 3 remainder 2.
  • An improper fraction has a top number bigger than its bottom number.
Worked example 3.3.1
Write 2 3/4 as an improper fraction.

Method. Multiply the whole number by the bottom, then add the top.

  1. Multiply the whole number by the bottom number. Each whole has 4 parts, so 2 wholes have 2 × 4 parts.
    2 × 4 = 8
  2. Add the top number. Add the 3 parts that are left over.
    8 + 3 = 11
  3. Keep the same bottom number. The size of each part does not change.
    11/4
  4. Write the answer.
    11/4

Check. 11/4 = 2 3/4, because 4 × 2 = 8 and 8 + 3 = 11. ✓

Worked example 3.3.2
Write 17/5 as a mixed number.

Method. Divide the top by the bottom: the whole number and the remainder make the mixed number.

  1. Divide the top number by the bottom number. 17 ÷ 5 = 3 with 2 left over.
    17 ÷ 5 = 3 r 2
  2. Write the answer as a mixed number. The whole number is 3, and the 2 left over goes over 5.
    3 2/5
  3. Write the answer.
    3 2/5

Check. 3 × 5 + 2 = 17. ✓

Watch out. The remainder goes on top of the same bottom: 2/5, not 2/3.

Worked example 3.3.3
Fill in the box with <, > or =: 2 1/3 ☐ 7/3.

Method. Change the mixed number to an improper fraction, then compare.

  1. The bottom numbers are the same. So compare the top numbers.
    7/3 and 7/3
  2. Compare the top numbers. 7 and 7 tell us which fraction is bigger.
    7 = 7, so 7/3 = 7/3
  3. Write the answer.
    =

Check. 2 1/3 = 7/3. ✓

Exercise 3C  Practice: mixed numbers and improper fractions

Non-calculator
1
FWrite 1 2/3 as an improper fraction.
2
FWrite 3 1/2 as an improper fraction.
3
FWrite 2 3/8 as an improper fraction.
4
FWrite 5 1/4 as an improper fraction.
5
FWrite 4 3/5 as an improper fraction.
6
FWrite 2 1/6 as an improper fraction.
7
FWrite 11/4 as a mixed number.
8
FWrite 17/6 as a mixed number.
9
FWrite 23/5 as a mixed number.
10
FWrite 14/3 as a mixed number.
11
FWrite 19/8 as a mixed number.
12
PSA baker has 4 3/8 kg of flour. Write this as an improper fraction, counting eighths.
13
PSA rope is 50/7 metres long. Write its length as a mixed number of metres.
14
RExplain why 9/4 is the same as 2 1/4.
15
PSWrite 13/4 as a mixed number.
16
FWrite 3 2/5 as an improper fraction.

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