© Boardworks Ltd 2004 1 of 56 Calculating with fractions Fraction Mathematics in Primary Schools.
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Transcript of © Boardworks Ltd 2004 1 of 56 Calculating with fractions Fraction Mathematics in Primary Schools.
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© Boardworks Ltd 2004 1 of 56
Calculating with fractions
Fraction Mathematics in Primary Schools
![Page 2: © Boardworks Ltd 2004 1 of 56 Calculating with fractions Fraction Mathematics in Primary Schools.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697bfd01a28abf838caa5b4/html5/thumbnails/2.jpg)
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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
![Page 8: © Boardworks Ltd 2004 1 of 56 Calculating with fractions Fraction Mathematics in Primary Schools.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697bfd01a28abf838caa5b4/html5/thumbnails/8.jpg)
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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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© Boardworks Ltd 2004 10 of 56
When we multiply by a fraction we:
multiply by the numerator
and
divide by the denominator
Multiplying fractions
![Page 11: © Boardworks Ltd 2004 1 of 56 Calculating with fractions Fraction Mathematics in Primary Schools.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697bfd01a28abf838caa5b4/html5/thumbnails/11.jpg)
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Exercise A Work out the following
1) 2 1 2) 2 4 3) 6 2 4 3 5
4) 2 10 5) 4 7 6) 3 123 9 5
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Counting on and back using fractions
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Presentation By
MD SABBIR HOSSAIN (010-066)
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Thank you all.