Page 79 - ICSE Math 5

Prime Factorization Method
Step 1: Find the prime factors of 15 and 25, and identify the common prime
factors.

Prime factors of 15 are 3 and 5.

Prime factor of 25 is 5 (5 × 5 = 25).
Common prime factor of 15 and 25 is 5.

Step 2: Since there is only one common factor
Top Tip
of 15 and 25, we cannot find the
product of common factors. Keep dividing the
fraction by its common
Step 3: Divide the numerator and denominator factor until you have no
of the fraction by 5. common factor except
1 to divide it further.
15 ÷ 5 = 3
25 ÷ 5 5

15 3
So, the lowest terms of is .
25 5
Converting Improper Fraction to Mixed Fraction

To convert an improper fraction to a mixed fraction, we follow the given steps.

• Divide the numerator by the denominator.
• Write the quotient as the whole number, remainder as the numerator and divisor as the
denominator of the fractional part.

Remainder
Mixed fraction = Quotient
Divisor
24
Example 6: Convert to mixed fraction. Mental Maths
17
1. Write the following in their lowest
1
terms.
Solution: 17 2 4 10 25 500
(a) (b) (c)
– 1 7 100 125 1000
7 2. Convert to mixed fractions.
15 26 100
24 7 (a) (b) (c)
So, = 1 . 4 6 3
17 17
Alternatively,

Split the numerator in such a way that one number is completely divisible by the
denominator and then solve it.

24 17 + 7 17 7 7 7
= = + = 1 + = 1
17 17 17 17 17 17
24 7
So, = 1 .
17 17

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