Percentages to Decimal

The percent symbol means 'divided by 100' which means that the decimal point has to be moved two places to the left. The following examples demonstrate this:

2% =
2
100
= 0.02
15% =
15
 
100
= 0.15
150% =
150
 
100
= 1.5
200% =
200
 
100
= 2
12½% = 12.5% =
12.5
 
100
= 0.125
33   %
=
1
 
3
= 0.33 correct to 2 decimal places

Examples:

15% of £60 is the same as
15
 
100
of £60 which is:
15
 
100
× £60 = 0.15 × £60 = £9
4% of 150ml is the same as
4
 
100
of 150ml which is:
4
 
100
× 150ml = 0.04 × 150ml = 6ml

Percentages which are more than 100% are less often found, but they can be interpreted in the usual way.

200% of £40 is the same as
200
 
100
of £40 which is:
200
 
100
× £40 = 2 × £40 = £80

Similarly; 120% of 50g is the same as

120
 
100
× 50g = 1.2 × 50g = 60g

Task 21