Year 6 · Arithmetic skills · Skill 8A

Skill 8A: Percentages of amounts

Find a percentage of an amount by building it from 10%, 5% and 1%.

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Each file is an editable Word document (.docx) with 25 questions in five columns. It opens in Word, Google Docs, Pages and LibreOffice, so you can change questions or add working space before printing.

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Worked examples

To find a percentage of an amount without a calculator, build it from easy pieces: 10%, 5% and 1%. Percent means “out of 100”.

Example 1

Building 38% from 10% and 1%

38% of 450

Find 10% by dividing by 10: 450 ÷ 10 = 45. Find 1% by dividing by 100: 450 ÷ 100 = 4.5.
38% is 3 tens and 8 ones, so it is 3 × 10% and 8 × 1%.
Building block How to find it Value
10% 450 ÷ 10 45
30% 3 × 45 135
1% 450 ÷ 100 4.5
8% 8 × 4.5 36
Add the pieces: 135 + 36 = 171. So 38% of 450 = 171.

Building block	How to find it	Value
10%	450 ÷ 10	45
30%	3 × 45	135
1%	450 ÷ 100	4.5
8%	8 × 4.5	36

Answer: 171

Example 2

Using 5% as half of 10%

15% of 360

10% of 360 is 360 ÷ 10 = 36.
5% is half of 10%: 36 ÷ 2 = 18.
15% = 10% + 5% = 36 + 18 = 54. So 15% of 360 = 54.

Answer: 54

Top tips

10% is ÷ 10, 1% is ÷ 100, 5% is half of 10%.
Make the percentage from pieces you already know.
Some percentages are neat fractions: 50% is a half, 25% is a quarter.

Watch out for

Dividing by 10 when you need to divide by 100 for 1%.
Forgetting to add the pieces back together at the end.

Try some questions

These are from the worksheet. Work each one out, then open it to check.

12% of 250 =

Show the answer
30
28% of 350 =

Show the answer
98
44% of 350 =

Show the answer
154
88% of 375 =

Show the answer
330

All arithmetic skills

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