Adding fractions · Year 7
In Year 7 you learn: adding mixed numbers.
You can only add fractions when the pieces are the same size, so the denominators must match. If they don’t, change the fractions to equivalent fractions with a common denominator first, then add the numerators.
Key facts
- Different denominators: first change both to a common denominator (the lowest common multiple is easiest). Then add or subtract.
- Mixed numbers: add the wholes and the fractions separately, or turn both into improper fractions.
- If the answer is an improper fraction, you can write it as a mixed number: 19/12 = 1 7/12.
Worked examples
Example 1
Work out 1/2 + 3/8.
Answer: 7/8
Example 2
Work out 2/3 + 1/4.
Answer: 11/12
Example 3
Work out 3/4 + 5/6.
Answer: 1 7/12
Example 4
Work out 1 3/5 + 2 2/3.
Answer: 4 4/15
Example 5
Work out 1 5/6 + 2 3/4.
Answer: 4 7/12