Adding fractions · Year 4
In Year 4 you learn: adding fractions with the same denominator.
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
- Same denominator: add or subtract the tops. The bottom stays the same.
- Never add the bottoms: 1/2 + 1/3 is not 2/5.
- Simplify the answer at the end.
Worked examples
Example 1
Work out 2/7 + 3/7.
Answer: 5/7
Example 2
Work out 1/5 + 2/5.
Answer: 3/5
Example 3
Work out 3/8 + 1/8.
Answer: 1/2
Example 4
Leo eats 2/8 of a pizza and Amy eats 3/8 of the same pizza. How much of the pizza do they eat altogether?
Answer: 5/8 of the pizza