3h
expressing one quantity as a percentage
eg; express the following as a percentage
a) 12 out of 50
12/50 x 100/1 50 = 24%
becomes;
12/1 x 2/1 = 24%
goes into 100 twice
b) 13 out of 40
13/40 x 100/1 = 130/4 = 32.5
13/4(0) x 10(0)/1 cross out 1 0 in 100 and 40
c) 60 cents out of $5
60/500 x 100/1 (cross out all the 0s)
=60/5 = 12%
d) 200m out of 4km
200/4000 x 100/1 = 20000/4000 = 5%
cross out 2 zeros from 200/4000
cross out 3 zeros from 20000/4000
finding a percentage
eg find;
a) 5% of 4000
5/100 x 4000/1 = 200
cross 2 0s out
b) 50% or 20
50/100 x 20/1 = 10
(50/100 = 1/5)
c) 10% of 90
10/100 x 90/1 = 900/100 = 9
d) 120% of 20
120/100 x 20 = 24
cut out all the 0s
3h;
12 out of 40
12 divided by 40 = 0.3
0.3 x 100 = 30%
44 out of 55
44 divided by 55 = 0.8
0.8 x 100 = 80%
6 out of 16
6 divided by 16 = 0.375
0.375 x 100 = 37.5%
12 out of 18
12 divided by 18 = 0.66666
0.6666 x 100 = 66 2/3%
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