Percentages without a calculator

What is a Percentage

Percentage as a Fraction Simplify Answer

Percentage to a Decimal

Fraction to a Percentage

Percentages and Common Fractions

Match Percentages to Common Fractions

Use Common Fraction to solve a Perentage

Finding 5%

What is a Percentage

Which is the bigger

3

5

5

9

or

Difficult to tell without “ doing some Maths”

To make comparing fractions ( part of ) easier a special fraction called a Percentage was introduced

Percentage is a

fraction out of 1007 per cent is written as 7% and equals

7

100

What is a percentage

Setup

0

1 2 3

4 5 6

7 8 9

C

.

÷

x

0

+

On

²

-

Ans

=

√

Type in a number for the percentage then click the arrow

38 % is38

100

38

% means out of 100

38% means

38

100

38Out of

100

What is a percentage

Setup

0

1 2 3

4 5 6

7 8 9

2

C

.

÷

x

0

+

On

²

-

Ans

=

√

32 % is32

100

32

% means out of 100

32% means

32

100

32Out of

100

16

50=

8

25=

Hide Fraction

÷ 2

÷ 2

÷2

÷2

Percentage to a decimal

To change a percentage to a decimal divide the number in front of the % by 100

28% = 28 ÷ 100 = 0.28

7% = 7 ÷ 100 = 0.07

91% = 91 ÷ 100 = 0.91

Changing a percentage to a decimal is like changing pence to poundsThe next slide allows you to practice. Type a whole number for the percentage on the calculator then click the arrow

Percentage to a Decimal

Setup 110 1 2 3 4

5 6 7 8 98÷100

C

.

÷x

0.08+ On

²

-

Ans

=

√(-)

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

8% = 8 ÷ 100 = 0.08

1% 2% 3% 4% 5% 6% 7% 8% 9% 10%

0.01

0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1

0%

0

Enlarge

Hide Scale

Fraction to a Percentage

Step 1 :Change the Fraction to a decimal by dividing the top number by the bottom

Step 2 :To change the decimal to a percentage multiply by 100 and add the % sign

110 1 2 3 4

5 6 7 8 9Ansx100

C

.

÷x

62.5+ On

²

-

Ans

=

√(-)

5

8

= 5 ÷ 8 0.625=

0.625 x 100%

62.5=

Start Next

%

Fraction to a Percentage

Setup 110 1 2 3 4

5 6 7 8 9

C

.

÷x

0+ On

²

-

Ans

=

√(-)

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

81%

82% 83% 84% 85% 86% 87% 88% 89% 90%

0.81

0.82 0.83 0.84 0.85 0.86 0.87 0.88 0.89 0.9

80%

0.8

Hide Scale

4

5

= = = % =

%

Next

Percentages and Common Fractions

0

1 2 3

4 5 6

7 8 9

C

.

÷

x

0

+

On

²

-

Ans

=

√

20

1% 5%

Percentage

Fraction

20%

10%

20% 25% 33⅓% 50% 66⅔%

=

mult5%m

mult

mult mult1%m

20 % of

Setup

Click a Percentage then enter the equivalent Fraction

Match % to Fraction

1%

75%

10%

20% 25%

33⅓% 50% 66⅔%

101

41

1001

31

51

21

32

43

Start101

51

41

31

21

32

43

test

1001

Percentages and Common Fractions

Setup

0

1 2 3

4 5 6

7 8 9

302÷4

C

.

÷

x

75.5

+

On

²

-

Ans

=

√25 % of

1

4

1% 5%

Percentage

Fraction

25%

10%

20% 25% 33⅓% 50% 66⅔%

= 25%

187.2

=1

4x 187.2

=

=

New Example

mult5%m

mult

mult mult1%m

Calculating 5%

5% of 240(a) 10% of 240=

=

110 1 2 3 4

5 6 7 8 9

C

.

÷x

0+ On

²

-

Ans

=

√(-)(b) 5% of 240= =

Find 10% then half the answer

Next

All All

Finding 5%

The fraction for 5% is

1

20

5% of 630 =

1

20of630 630 =

20

Divide by Bottom

÷

Multiply by Top

x1

Dividing by 20 can be done in two steps

=31.5

Step 1 Dividing by 10

Step 2 Dividing by 2

Which is the same as

Step 1 Find 10%

Step 1 Half to find 5%

See Next slide

630÷10=63

63÷2=31.5