GCSE maths summary

Topic/Skill Definition/Tips
Topic: Basic Percentages Example
1. Percentage Number of parts per 100. 31
31 %means
100
2. Finding To find 10%, divide by 10 10% of £36 = 36÷10=£3.60
10%

3. Finding 1% To find 1%, divide by 100 1% of £8 = 8÷100 = £0.08


4. Percentage Difference A games console is bought for £200
×100 %
Change Original and sold for £250.

50
% change = ×100=25 %
200

5. Fractions to Divide the numerator by the 3
=3 ÷ 8=0.375
Decimals denominator using the bus stop method. 8

6. Decimals to Write as a fraction over 10, 100 or 1000 36 9
0.36= =
Fractions and simplify. 100 25

7. Percentages Divide by 100 8 %=8 ÷ 100=0.08
to Decimals

8. Decimals to Multiply by 100 0.4=0.4 × 100 %=40 %
Percentages

9. Fractions to Percentage is just a fraction out of 100. 3 12
= =12%
Percentages Make the denominator 100 using 25 100
equivalent fractions.
When the denominator doesn’t go in to 9
×100=52.9 %
100, use a calculator and multiply the 17
fraction by 100.
10. Percentage is just a fraction out of 100. 14 7
14 %= =
Percentages to Write the percentage over 100 and 100 50
Fractions simplify.




Mr A. Coleman Glyn School