I am learning to work out percentages of amounts.
%
Percentages are out of 100.
100

0
Tim got 18 out of 25 in a test and Scott got 45 out of 50 in a test. Who got the best result ?
We need to change the tests into percentages so that we can compare them.
Let’s start by changing Tim’s score (18 out of 25) into a percentage.
Multiplying the numerator and denominator by 4 will give us an equivalent fraction out of 100
18
25
X 4
72
100
18 72
25 50 75 100
72%
X 4

0
Now we need to turn Scott’s score (45 out of 50 into a percentage).
Multiplying the numerator and denominator by 2 will give us an equivalent fraction out of 100
45
50
X 2
90
100
45 90
25 50 100 75
X 2
90%
Tim scored 72% and Scott scored 90%. It is now easy to see that Scott got the best result.

Room 13 completed a maths test out of 40. Help the teacher convert some student scores into percentages.
If the test is out of 40. What would 50% be?
What would 25% be? Tip: 25% is half of a half.
What would 75% be? Tip: a half plus one quarter.
0 10 20 30 40
0% 25% 50% 75% 100%
The number line above is called a double number line. You can see it is very helpful to imagine when converting scores into percentages.

Room 9 completed a science quiz which was out of 16. Help the teacher convert some student scores into percentages.
If the test is out of 16. What would 50% be?
What would 25% be? Tip: 25% is half of a half.
What would 75% be? Tip: a half plus one quarter.
What would a score of 2 out of 16 be as a percentage?
You can see that 2 is exactly halfway between 0 and 25%.
Half of 25% is 12.5%.
0 2 4 8 12
0% 12.5% 25% 50% 75%
16
100%

Now try these questions on your own.
Change these fractions into percentages
Click again when you have worked out all your answers.
9
6
1)
24
25%
6)
27
2)
8
16
50%
7)
5
25
12
8)
3)
24
48
50% 25
9
8 9)
4) 25%
6
32
33%
20%
48%
150%
5)
2
20%
10)
12
75%
10 16
Need some more practise? Try pg34 & 35 of Teacher Tools Fractions,
Decimals and Percentages Book Numeracy resources