Decimals · Usually met around P4
Starting percentages
50% a half, 25% a quarter, 10% a tenth.
How to do it
Method
50% a half, 25% a quarter, 10% a tenth
25% of 80 = 80 ÷ 4 = 20
Another way
Halve, then halve again
80 → 40 → 20
In full
A percentage (%) means so many out of every 100: 37% is 37 parts of 100, that is 37100 = 0.37. On a hundred square, 37 of the 100 squares shaded is 37% shaded; all 100 is 100%. Remember a few: 50% is a half, 25% a quarter, 10% a tenth. So 50% of 80 is 80 ÷ 2 = 40, 25% of 80 is 80 ÷ 4 = 20, and 10% of 80 is 80 ÷ 10 = 8. Another way: 25% is half of 50%, so halve, then halve again: 80 → 40 → 20.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
16100 = □%
Show the answer and working
Answer: 16
16 out of every 100 is 16%.
Example 2
50% of 24 is □.
Show the answer and working
Answer: 12
50% is 12 of 24: 24 ÷ 2 = 12.
Example 3
The big square is cut into 100 equal squares. 83% of it is shaded.
True or false?
Show the answer and working
Answer: False
17 squares are shaded, 17%; the 83 unshaded are 83%.
Practise it in the game →Decimals · Free to start, unlimited questions, no download