Choose exam board for KS4 Computer Science (GCSE)
Choose exam board for KS4 English
Choose exam board for KS4 French
Choose exam board for KS4 Geography
Choose exam board for KS4 German
Choose exam board for KS4 History
Choose tier for KS4 Maths
Choose exam board for KS4 Music
Choose exam board for KS4 Physical education (GCSE)
Choose exam board for KS4 Religious education (GCSE)
Choose exam board for KS4 Spanish

Use knowledge of calculating common percentages of a number to solve problems in a range of contexts

Lesson details

Learning outcome

I can use common percentages of a number to solve problems.

Key learning points

  1. Addition, subtraction, multiplication and division can be used to calculate a new percentage from known percentages.
  2. For example, if I know 10% of a number, I can halve it to find 5%
  3. If I know 10% and 5% of a number, I can add them to find 15%

Keywords

  • Efficient - Efficient means working in an organised way without wasting time or effort.

  • Percentage - A percentage is a proportion of a whole.

Common misconception

Pupils may find calculating 75% of a number difficult.

First focus on teaching one strategy for finding 75% of a number. Pupils may find it easiest to add 50% and 25% together. Show representations of this (e.g. bar models showing the proportion of the whole) alongside calculations.

Teacher tip

Pupils need to be familiar with finding 50% and 10% of an amount before accessing this lesson. Throughout, make links between percentages and fractions explicit to support calculation (e.g. 10% is equal to one-tenth, 75% is equal to three-quarters).

Licence

This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0
except where otherwise stated. See Oak's terms & conditions
(Collection 2).

Lesson video

Loading...

Prior knowledge starter quiz

6 Questions

Q1.
Match the percentages and fractions that are equivalent.

Correct Answer:50%,$$ {1} \over {2} $$

$$ {1} \over {2} $$

Correct Answer:10%,$$ {1} \over {10} $$

$$ {1} \over {10} $$

Correct Answer:1%,$$ {1} \over {100} $$

$$ {1} \over {100} $$

Q2.
100% of a number is 240 Use this to match the percentages to the value.

Correct Answer:1% of 240,2.4

2.4

Correct Answer:50% of 240,120

120

Correct Answer:10% of 240,24

24

Q3.
One of the stages of the Tour de France race is 205 km long. Match the percentage of the race to the number of km.

Correct Answer:100% of 205 km,205 km

205 km

Correct Answer:50% of 205 km,102.5 km

102.5 km

Correct Answer:10% of 205 km,20.5 km

20.5 km

Correct Answer:1% of 205 km,2.05 km

2.05 km

Q4.
A rider has completed 50% of a different stage of the race. If they have ridden 88 km, what is the length of the whole race? km

Correct Answer: 176

Q5.
If 100% of a number is 110, what is 1% of the number?

Correct Answer: 1.1

Q6.
If 10% of a number is 46.5, what is 100% of the number?

Correct Answer: 465

6 Questions

Q1.
Match the fractions and the percentages.

Correct Answer:one-half,50%

50%

Correct Answer:one-quarter,25%

25%

Correct Answer:one whole,100%

100%

Correct Answer:three-quarters,75%

75%

Q2.
What is one half of 50%? %

Correct Answer: 25

Q3.
Find 25% of these numbers.

Correct Answer:25% of 100,25

25

Correct Answer:25% of 88,22

22

Correct Answer:25% of 200,50

50

Correct Answer:25% of 160,40

40

Correct Answer:25% of 140,35

35

Q4.
75% is three one-quarters or $$ {3} \over {4} $$ so what is 75% of 240 km? km

An image in a quiz
Correct Answer: 180

Q5.
Use this fact to calculate other percentages. 100% is 120 km

Correct Answer:50 % of 120 km,60 km

60 km

Correct Answer:10% of 120 km,12 km

12 km

Correct Answer:70% of 120 km,84 km

84 km

Correct Answer:20% of 120 km,24 km

24 km

Correct Answer:5% of 120 km,6 km

6 km

Q6.
If 100% is 250 km, use an efficient method to find 20% of 250 km km

Correct Answer: 50

To help you plan your 6 maths lesson on: Use knowledge of calculating common percentages of a number to solve problems in a range of contexts, download all teaching resources for free and adapt to suit your pupils' needs...