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

Starter quiz

Match the percentages and fractions that are equivalent.

50%

⇔

${1} \over {2}$ ✓

10%

⇔

${1} \over {10}$ ✓

1%

⇔

${1} \over {100}$ ✓
100% of a number is 240 Use this to match the percentages to the value.

1% of 240

⇔

2.4 ✓

50% of 240

⇔

120 ✓

10% of 240

⇔

24 ✓
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.

100% of 205 km

⇔

205 km ✓

50% of 205 km

⇔

102.5 km ✓

10% of 205 km

⇔

20.5 km ✓

1% of 205 km

⇔

2.05 km ✓
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

'176' ✓
If 100% of a number is 110, what is 1% of the number? ______

'1.1' ✓
If 10% of a number is 46.5, what is 100% of the number? ______

'465' ✓

Exit quiz

Match the fractions and the percentages.

one-half

⇔

50% ✓

one-quarter

⇔

25% ✓

one whole

⇔

100% ✓

three-quarters

⇔

75% ✓
What is one half of 50%? ______%

'25' ✓
Find 25% of these numbers.

25% of 100

⇔

25 ✓

25% of 88

⇔

22 ✓

25% of 200

⇔

50 ✓

25% of 160

⇔

40 ✓

25% of 140

⇔

35 ✓
$75% is three one-quarters or <Math> {3} \over {4} </Math> so what is 75% of 240 km? <span class="blank">______</span> km$

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

'180' ✓
Use this fact to calculate other percentages. 100% is 120 km

50 % of 120 km

⇔

60 km ✓

10% of 120 km

⇔

12 km ✓

70% of 120 km

⇔

84 km ✓

20% of 120 km

⇔

24 km ✓

5% of 120 km

⇔

6 km ✓
If 100% is 250 km, use an efficient method to find 20% of 250 km ______ km

'50' ✓

Worksheet

Loading worksheet ...

Presentation

Loading presentation ...

Video

Lesson Details

Key learning points

Addition, subtraction, multiplication and division can be used to calculate a new percentage from known percentages.
For example, 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%

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.

Keywords

Efficient - Efficient means working in an organised way without wasting time or effort.
Percentage - A percentage is a proportion of a whole.