Maths Library

Adding and Subtracting Fractions: Year 8 maths

Pupils practise addition and subtraction of fractions with both like and unlike denominators. The exercises build from simple common denominator sums up to operations involving mixed numbers.

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What this covers

Adding and Subtracting Fractions is taught in Year 8 (age 13 to 14) as a topic to introduce. It sits in the Fractions strand.

Worked example

Calculate 23 + 14.

  1. Find a common denominator: the lowest common multiple of 3 and 4 is 12.
  2. Convert each fraction: 23 = 812 and 14 = 312.
  3. Add the numerators: 812 + 312 = 1112.

Answer: 1112

Difficulty scale

The sheet generator offers five difficulty settings for this topic.

  1. Adding and subtracting fractions with identical denominators under 12
  2. Operations where one denominator is a multiple of the other
  3. Operations with unlike denominators requiring a common multiple up to 24
  4. Addition and subtraction resulting in improper fractions that must be simplified
  5. Adding and subtracting mixed numbers with regrouping

Common mistakes

  • Adding both numerators and denominators together (e.g. 1/3 + 1/3 = 2/6)
  • Subtracting the smaller whole number from the larger without regrouping fractional parts

Curriculum links

Indicative matches to Australian Curriculum v9. Check wording and codes against the official document.

  • AC9M8N03 Perform calculations with negative fractions, decimals, and mixed operations with integers.

Sample sheet and answers

Six questions at the level's usual difficulty. Open the editor to change, add or regenerate any of them.

Adding and Subtracting Fractions

Year 8 maths

Qs
6
Marks
18
NameDateScore / 18
1.
22 − 26 =
[3]
2.
26 + 23 =
[3]
3.
19 + 62 =
[3]
4.
35 − 27 =
[3]
5.
79 − 14 =
[3]
6.
711 + 16 =
[3]

Answer key

  1. 23Common denominator 6; 6/6 − 2/6 = 4/6
  2. 1Common denominator 6: 2/6 + 4/6; = 6/6, which simplifies to 1
  3. 319Common denominator 18: 2/18 + 54/18; = 56/18, which simplifies to 319
  4. 1135Common denominator 35; 21/35 − 10/35 = 11/35
  5. 1936Common denominator 36; 28/36 − 9/36 = 19/36
  6. 5366Common denominator 66: 42/66 + 11/66; = 53/66, which simplifies to 5366