Use knowledge of calculating any percentage of a number to solve problems in a range of contexts | Maths

Starter quiz

Find 10% of these numbers.
- 10% of 180
  
  ⇔
  
  18 ✓
- 10% of 450
  
  ⇔
  
  45 ✓
- 10% of 130
  
  ⇔
  
  130 ✓
- 10% of 3,000
  
  ⇔
  
  300 ✓
- 10% of 130
  
  ⇔
  
  13 ✓
Find 25% of these numbers.
- 25% of 120
  
  ⇔
  
  30 ✓
- 25% of 104
  
  ⇔
  
  26 ✓
- 25% of 300
  
  ⇔
  
  75 ✓
- 25% of 1,200
  
  ⇔
  
  300 ✓
- 25% of 1,000
  
  ⇔
  
  250 ✓
Find 75% of these numbers.
- 75% of 120
  
  ⇔
  
  90 ✓
- 75% of 400
  
  ⇔
  
  300 ✓
- 75% of 1,000
  
  ⇔
  
  750 ✓
- 75% of 600
  
  ⇔
  
  450 ✓
- 75% of 1,500
  
  ⇔
  
  1,125 ✓
What number is 1% of 150? ______
- '1.5' ✓
Use this fact to calculate other percentages. 100% is 160 km
- 50% of 160 km
  
  ⇔
  
  80 km ✓
- 10% of 160 km
  
  ⇔
  
  16 km ✓
- 40% of 160 km
  
  ⇔
  
  64 km ✓
- 5% of 160 km
  
  ⇔
  
  8 km ✓
- 1% of 160 km
  
  ⇔
  
  1.6 km ✓
If 100% is 450 km, use an efficient method to find 60% of 450 km ______ km
- '270' ✓

Exit quiz

How can you find the percentages of different numbers?
- 10%
  
  ⇔
  
  Divide by 10 ✓
- 25%
  
  ⇔
  
  Divide by 4 ✓
- 1%
  
  ⇔
  
  Divide by 100 ✓
- 75%
  
  ⇔
  
  Add 50% and 25% together ✓
- 5%
  
  ⇔
  
  Halve 10% ✓
If 100% is £400, find these percentages.
- 50% of £400
  
  ⇔
  
  £200 ✓
- 10% of £400
  
  ⇔
  
  £40 ✓
- 1% of £400
  
  ⇔
  
  £4 ✓
- 25% of £400
  
  ⇔
  
  £100 ✓
- 75% of £400
  
  ⇔
  
  £300 ✓
Lucas needs to find the number of children who cycled to school. Look at the pie chart and complete each step of the table to calculate 21% of 300 children ______
- '63' ✓
Aisha’s battery has 69% of 600 minutes left. Complete each step of the table to calculate 69% of 600 minutes. ______ minutes
- '414' ✓
Look at the table and find the missing percentage. 10 = ______% of 50
- '20' ✓
Use the table to calculate the missing percentage. 125 = ______% of 500
- '25' ✓

Worksheet

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Presentation

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Lesson Details

Key learning points

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

Common misconception

Pupils may confuse the numbers given and the percentages of them when calculating.

In the lesson, calculating with the numbers given (from 3 to 90) and the percentages of them (e.g. 1% to 30%) is often dealt with separately, looking at individual columns in a table. Columns can be covered when calculating to help focus attention.

Keywords

Percentage - A percentage is a proportion of a whole.