Percentages

Working out Percentages of a number

Practise some more here

Percentages Booklet

A Half can be written…
As a fraction:
1/2
As a decimal:
0.5
As a percentage:
50%

 

A Quarter can be written…
As a fraction:
1/4
As a decimal:
0.25
As a percentage:
25%

Here, have a play with it yourself:

Example Values

Here is a table of commonly occuring values shown in Percent, Decimal and Fraction form:

Percent Decimal Fraction
1% 0.01 1/100
5% 0.05 1/20
10% 0.1 1/10
12½% 0.125 1/8
20% 0.2 1/5
25% 0.25 1/4
331/3% 0.333… 1/3
50% 0.5 1/2
75% 0.75 3/4
80% 0.8 4/5
90% 0.9 9/10
99% 0.99 99/100
100% 1
125% 1.25 5/4
150% 1.5 3/2
200% 2

 

From Fraction to Decimal

The easiest way to convert a fraction to a decimal is to divide the top number by the bottom number (divide the numerator by the denominator in mathematical language)

Example: Convert 2/5 to a decimal

Divide 2 by 5: 2 ÷ 5 = 0.4

Answer: 2/5 = 0.4

 

From Decimal to Fraction

To convert a decimal to a fraction needs a little more work.

Example: To convert 0.75 to a fraction

Steps Example
First, write down the decimal “over” the number 1
0.75
1
Multiply top and bottom by 10 for every number after the decimal point (10 for 1 number, 100 for 2 numbers, etc)
0.75 × 100
1 × 100
(This makes a correctly formed fraction)
75
100
Then Simplify the fraction
3
4

 

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