Adding and subtracting fractions · Grade 4
In Grade 4 you learn: adding and subtracting fractions with the same denominator.
You can only add or subtract fractions when the pieces are the same size, which means the denominators must match. If they don’t, rewrite the fractions as equivalent fractions with a common denominator first.
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 3/8 + 1/8.
Answer: 1/2
Example 2
Sipho earns £12,000 a month. He spends 1/4 of it on rent and 1/3 on food. How much is left?
Answer: £5,000