Percentages

Question 1

Simple percentages

Answer 1

16% of £82

Find 10% of 82, 1% and 5% then add together. = 13.12

Question 2

Working out percentages - using calculator

Answer 2

Turn the percentage into a decimal by / by 100.

Then times by what your need the percentage of.

Eg 26% of 58 = 0.26 x 58 = 15

Question 3

Expressing one number as a percentage of another

Answer 3

% = 7/20

Then the bottom out of 100
Eg 7/20 = 35/100 (times both by 5) whatever you do to the top remember to do to the bottom.

Question 4

Expressing one number as a percentage of another r- using calculator

Answer 4

18/25 x 100 = 51.4%

Question 5

The order of operations

Answer 5

BIDMAS
Brackets
Indices (powers)
Division
Multiplication
Addition
Subtraction

Question 6

increasing percentages

Answer 6

increase £18 by 12%
make it 0.12 but add a 1 so 1.12
18x1.12=£20.16

Question 7

decreasing percentages

Answer 7

for decreasing with the percent go backwards from 100
decrease 70 by 34%
0.66x70=46.2 (don’t add a 1 before decimal point)

Question 8

finding the percentage change (increasing or decreasing)

Answer 8

first do the two different units a - them eg
£420-£370=50
formula=change(50)/original(420)x100=11.9

Question 9

Finding the original amount

Answer 9

to work out the original price of a bike increased by 15% to £345
originalx1.15=345
to find the original price reverse this
345/1.15=300(original amount)