Fractions of Amounts (AQA GCSE Maths: Foundation): Revision Note

Fractions of amounts

How do I find a fraction of an amount?

• Method 1
  Divide by the denominator and multiply by the numerator

  • To find $\frac{1}{3}$ of $90$, divide it by 3

    • $90÷3=30$

  • To find $\frac{2}{5}$ of $60$, divide it by 5 then multiply it by 2

    • $60÷5=12$, then $12\times 2=24$

• Method 2
  Change the fraction into a decimal, then multiply

  • To find $\frac{1}{4}$ of $16$, turn $\frac{1}{4}$ into $0.25$ then multiply

    •  $0.25\times 16=4$

  • To find $\frac{9}{10}$ of $15$, turn $\frac{9}{10}$ into $0.9$ then multiply

    •  $0.9\times 15=13.5$

• Method 3
  Write both numbers as fractions and multiply two fractions together

  • To find $\frac{2}{3}$ of $60$, write $60$ as $\frac{60}{1}$

    • work out $\frac{2}{3}\times \frac{60}{1}=\frac{120}{3}=40$

  • To find $\frac{5}{6}$ of $\frac{8}{3}$

    • work out $\frac{5}{6}\times \frac{8}{3}=\frac{40}{18}=\frac{20}{9}$