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NZAMT NZQA NZ Grapher NZ Maths Census at School Study It

Percentages of

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10

Percentage of an amount

Review of percentages.
Converting fraction to decimal to %

Calculating the percentage of an amount

Calculating the original amount by dividing.

Khan Video Tutorial: Conversions | Video 1 | Video 2

 

 

% of an amount Class notes | pdf

Conversions Class Notes | pdf

Decimal Fraction % p346 Ex 24.01 #1-4
p29 Ex 3.01

Percentage of: p346 Ex 24.01 #5,6

Finding original amount p346 Ex 24.01 #7
p30 Ex 3.02 Answers A | B | C

NuLake p17,18,19

 

Converting Fractions / Decimals / Percentages

Fraction

Decimal

Percentage

1/20

0.05

5%

24/60

0.4

40%

4 1/8

4.125

412.5%

4/25

0.16

15%

3/500

0.006

0.6%

24/5

2.8

280%

13/20

0.65

65%

12/5

1.4

140%

1/4000

0.0.00025

0.025%

Mouse over for answers

Converting between:

 

Fraction

Decimal

 

Use Calculator Key

 

 

 

Converting between:

 

Decimal

Percentage

 


Divide by 100  or   Multiply by 100

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Percentage Of...

Find 28% of something

 

 

Question

Working

Answer

28% of $520

$520 x 28/100

(or) $520 x 0.28

$145.60

 

 

 

4% of $84

$84 x 4/100

(or) $84 x 0.04

$3.36

 

 

 

130% of $62

$62 x 130/100

(or) $62 x 1.3

$80.60

 

 

 

Calculator Use:
'Shift =' makes the % function:

62 x 130 %
62 x 130 'shift ='

(amount first, % second)

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Finding the original Amount

28% of something = the new value

How much was the original?

We Divide back....

New value 0.28 = Original

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