Page 160 - New Medley 5 Semester 1

1. Factor Tree Method

In this method, a number is repeatedly broken down into smaller
factors till all the factors are primes. For example,

36 or 36 or 36

2 × 18 4 × 9 3 × 12

2 × 2 × 9 2 × 2 × 3 × 3 3 × 3 × 4

2 × 2 × 3 × 3 3 × 3 × 2 × 2

Prime factorisation of 36 = 2 × 2 × 3 × 3.

2. Division Method

In this method, a number is divided repeatedly by prime numbers till
the quotient is 1.

For example, let us factorise 60 and 168.

260 2 168

230 2 84

315 2 42

5 5 3 21

1 7 7
1

Thus, 60 = 2 × 2 × 3 × 5 Thus, 168 = 2 × 2 × 2 × 3 × 7

EXERCISE 3.3

A. Fill in the blanks.
1. Even – Odd = 4. Even – Even =

2. ÷ Odd = Odd 5. – Even = Odd

3. Odd – = Even 6. Even ÷ Odd =

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