Grade 4 · Unit 2: Fractions and decimals

Calculating with fractions

Add, subtract, multiply and divide fractions.

A garden split into plots for different plants.

Fractions in the garden

Gardens, cakes and land are often shared in fractions. To add fractions with different denominators, we make the denominators the same. Then we can add, take away, multiply and divide.

Types of fraction

A proper fraction is less than one whole. An improper fraction is one whole or more: 7/4 = 1¾, a mixed number. A unit fraction has 1 on top.

Different denominators

½ and ⅓ cannot be added straight away. Change them to a common denominator: sixths. 3/6 + 2/6 = 5/6. Mixed numbers: add the wholes, then the fractions: 1½ + 2¼ = 3¾.

Fractions of amounts and multiplying

⅔ of 15: divide by 3, then multiply by 2: 10. “Of” means multiply: ⅔ × 15 = 10. Multiplying two fractions: ½ × ½ = ¼ – half of a half is a quarter.

Dividing with fractions

3 ÷ ½ asks: how many halves are in 3? The answer is 6. ¾ ÷ 3 shares three quarters between 3 people: each gets ¼. Use brackets and the order of operations: (½ + ¼) × 4 = ¾ × 4 = 3.

What I learnt