New
New
Year 10
Higher

Checking and securing understanding of percentage increase

I can increase an amount by a given percentage.

New
New
Year 10
Higher

Checking and securing understanding of percentage increase

I can increase an amount by a given percentage.

Lesson details

Key learning points

  1. In all of these representations a single multiplier can be used to find a percentage increase.
  2. Representation can help when you are not using a calculator.
  3. A multiplier is significantly faster when using a calculator.
  4. To increase, you are going above the original amount.

Common misconception

A single digit percentage is incorrectly worked out by dividing by 10 and not 100 e.g 3% = 0.3. This error continues when increasing amounts e.g increase 40 by 3% has a multiplier of 1.3

Remind pupils that to covert a percentage into a decimal we divide by 100. This applies with increase too e.g 120% has a multiplier of 1.2

Keywords

  • Proportion - If two things are proportional then the ratio of part to whole is maintained and the multiplicative relationship between parts is also maintained.

Using mini-whiteboards, pupils draw a 3 x 6 table with the following columns: original amount, percentage increase and new amount. For each row, they only fill in 2 pieces of information. They swap boards and their peer must work out the missing value. Return the MWB back for checking.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
Write 24 as a percentage of 400
Correct Answer: 6, 6%
Q2.
Write 18 as a percentage of 150
Correct Answer: 12%, 12
Q3.
Find 24% of 70
Correct Answer: 16.8
Q4.
Find 60% of 90
Correct Answer: 54
Q5.
Write 65 as a percentage of 500
Correct Answer: 13, 13%
Q6.
Find 216% of 856
Correct Answer: 1848.96

6 Questions

Q1.
Increase 250 by 5%
Correct Answer: 262.5
Q2.
Increase 250 by 6.4%
Correct Answer: 266
Q3.
Increase 500 by 0.71%
Correct Answer: 503.55
Q4.
A mathematician celebrates her shares increasing by 6.5%. They are now worth £426.00. How much did she originally invest?
Correct Answer: 400, £400
Q5.
If a number increases by 12% and is now 588, what was it originally?
Correct Answer: 525
Q6.
If a number increases by 26% and is now 77, what was it originally to 1 d.p.?
Correct Answer: 61.1