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Fraction as an Operator ‘of’
1
Ruhi has 20 rubber bands. She shares of rubber bands with her younger sister.
4
How many rubber bands are left with Ruhi?
To get the answer, first we have to understand that here, ‘of’ indicates multiplication.
1 1 20
So, Ruhi gave = of 20 rubber bands = × 20 = = 5 rubber bands to her
younger sister. 4 4 4
\ Rubber bands left with Ruhi = 20 – 5 = 15
Thus, ‘of’ is an operator of multiplication, and a fraction can Think and Answer
be used to 'operate' on a quantity. What is one-quarter
of a day?
Example 6: Evaluate the following.
3 1
(a) of 36 (b) of 96
4 4
3 3 3 × 36 1 1 1 × 96
Solution: (a) of 36 = ×36 = = 3 × 9 = 27 (b) of 96 = × 9 6 = = 24
4 4 4 4 4 4
www
MAths connect
1
The weight of an object on the moon’s surface is of the weight of the same object on Earth because the moon’s
1 6
gravity is of Earth’s gravity. What will be your weight on the moon’s surface if your weight on the earth surface
6
is 54 kg? Take help of the internet and collect information about the gravities of all planets in our solar system.
What is the relationship between their gravities and earth’s gravity respectively?
Multiplication of a Fraction by a Fraction
To multiply a fraction by another fraction, we follow the following steps:
1. Change mixed fraction into improper faction (if any).
2. Multiply the numerator of each fraction and similarly, multiply the denominators of both
Productofnumerators
fractions. That is the product of two fractions =
Productofdenominators
3. Reduce the fraction so obtained in its lowest form, if required.
For example:
×
2 1 21 2
(a) × = = For multiplication of more
5 3 53 15 Note: than two fractions, we
×
1 1 13 11 13 × 11 143 8 follow the same method as
(b) 4 × 2 = × = = = 9
×
3 5 3 5 35 15 15 we follow for two fractions.
Mathematics-7 36
