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Subject – Mathematics

Chapter 3 – FACTORS AND MULTIPLES

Sub-topic-3:- PRIME FACTORISATIONS

Expressing a given number as the product of prime numbers is called the prime
factorization of the given number.

 Write the primefactorisation using division method.

Step1: First we divide the number by the smallest prime number which divides
the number exactly.

Step2: We divide the quotient again by the smallest or the next smallest prime
number if it is not exactly divisible by the smallest prime number. We repeat
the process again and again till the quotient becomes 1. Remember, we use
only prime numbers to divide.

Step3: We multiply all the prime factors. Remember, the product is the number
itself.

Example1: Write the prime factorization of 80 by division method.

Step 1: First we will divide 80 by the smallest prime number, that is 2 and write the
quotient 40 below 80.

Step 2: Now again divide 40 by smallest prime number , that is 2 and write the quotient
20 below 40.

Step 3: Now again divide 20 by smallest prime number, that is 2 and write the quotient
10 below 20.