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Calculating with fractions

Fraction Mathematics in Primary Schools

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A1

Contents

Calculating with fractions

Multiplying fractions

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Multiplying fractions by integers

We can illustrate this calculation on a number line:

0

14

14

14

12

14

34

14

1

14

141

14

121

14

341

14

2

14

What is 8 × ?

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Again, we can illustrate this calculation on a number line:

0

34

34

34

121

34

142

34

3

34

343

34

124

34

145

34

6

34

346

34

127

34

148

34

9

34

What is 12 × ?

Multiplying fractions by integers

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Let’s use a number line again:

0

13

13

13

23

13

1

13

131

13

231

13

2

13

132

13

232

13

3

13

What is 9 × ?

Multiplying fractions by integers

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So,

8 × = 214

12 × = 934

9 × = 313

What do you notice?

What do you notice?

and

Multiplying fractions by integers

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Following the rules of arithmetic, we know that,

8 ×14

=14

× 8

In maths the word ‘of’ (এর) means ‘times’ (গুণ).

=14

of 8 = 8 ÷ 4

These are equivalent calculations.

Multiplying fractions by integers

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Means the same as:

35

20 ×

35

× 2035

of 2015

3 × of 20

20 × 3 ÷ 5 20 ÷ 5 × 3 3 ÷ 5 × 20

Equivalent calculations

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When we multiply a fraction by an integer we:

multiply by the numerator

and

divide by the denominator

For example,

49

54 × = 54 ÷ 9 × 4

= 6 × 4

= 24

Multiplying fractions by integers

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When we multiply by a fraction we:

multiply by the numerator

and

divide by the denominator

Multiplying fractions

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Exercise A Work out the following

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Presentation ByMD IMRAN HOSSAIN (010132)

Thank you all.