Like fractions and decimals, we use per cent to describe a proportion or a quantity. For example: in a test, Colm got 82 out of 100 questions right. We can write this as 82
___ 100, 0.82 or 82%.
1. Express these fractions as percentages: a) 27
___ 100
g) 88 ___
100 b) 3
___ 100
h) 65 ___
100
c) 42 ___
i)
100 71
___ 100
d) 16 ___
j)
100 94
___ 100
e) 31 ___
k) 12 ___
100 100
f) l)
___ 100
9 100
___ 100
2. There are 100 children in each school. From the information given in the table, can you work out the percentages of boys and girls in each school?
Number of girls
62 76 38
56
Fraction of girls
___ 100
62
Percentage of girls
Number of boys
38 24
71
Fraction of boys
___ 100
24
Percentage of boys
Total children
100 100 100 100 100
Fractions are not always written as hundredths, so before we change them to percentages, we need to write them as equivalent fractions with a denominator of 100.
_ = __ × ___ = ____ = 20% 5 5 20 100
1 1 20 20
3. Convert the fractions to hundredths and then percentages. a) 1
– 2 = ___
100 = % b) 7 __
10 c) 2
– 5
d) 1
– 4
4. What percentage of each of theses shapes is a) pink b) white? (Hint: write your answers as fractions first.)