Starter quiz
- Increase 600 by 5%
- '630' ✓
- Write 62 as a percentage of 200
- '31' ✓
- Increase 90 by 11%
- '99.9' ✓
- Find 11% of 700
- '77' ✓
- Write 50 as a percentage of 1250
- '4' ✓
- Find 90% of 625
- '562.5' ✓
Exit quiz
- Which statement is the equivalent of "Decrease 50 by 20%"?
- Work out 20% of 50
- Work out 80% of 50 ✓
- Divide 50 by 20
-
- Which statement is the equivalent of "Increase 130 by 15%"?
- Work out 115% of 130 ✓
- Work out 85% of 130
- Work out 15% of 130
-
- Which statement is the equivalent of "Decrease 700 by 35%"?
- Work out 35% of 700
- Work out 65% of 700 ✓
- Work out 85% of 700
-
- Decrease 700 by 4.5%
- '668.5' ✓
- Increase 700 by 4.5%
- '731.5' ✓
- Increase 700 by 18%
- '826' ✓
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- In all of these representations a single multiplier can be used to find a percentage decrease.
- Representation can help when you are not using a calculator.
- A multiplier is significantly faster when using a calculator.
- To decrease you are going below the original amount.
Common misconception
When using multipliers, pupils can mistake a decimal for the percentage decrease. e.g. 0.52 is a 52% decrease, rather than recognising a 48% decrease
Reminding students that a decimal multiplier greater than 1 means an increase, and a decimal multiplier less than 1 means a decrease. The latter requires a subtraction from 1 or 100%
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.
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