# CLASS-4H.C.F - PRIME FACTORIZATION METHOD

Finding H.C.F Via Prime Factorization Method -

HCF

1. PRIME FACTORIZATION METHOD : In this method

§ STEP 1.) First we find the prime factors of the given numbers separately by factorization.

§ STEP 2.) Then we underline the common prime factors of the numbers and write it down.

§ STEP 3.) We multiply the common prime factors

§ STEP 4.) The product of these common prime factors is the H.C.F of the given numbers.

SOLVED EXAMPLE:

Q. Find the HCF using PRIME FACTORIZATION METHOD.

210, 360, 150

Ans.) STEP 1.) Write the Prime Factors and do the red color the Common Factors

210 = 2 x              3 x       5 x 7 x  1

360 = 2 x 2 x 2 x 3 x 3 x       5      x 1

150 = 2 x              3 x       5 x 5 x 1

STEP 2.)

Common factors = 2 x 3 x 5 x 1    (Multiply the Common Factors)

STEP 3.)

H.C.F = 30              (The product is the H.C.F)

STEP 4.)

Answer: The HCF of 210, 360 and 150 is 30.    (Ans.)

Important Note -

Two numbers are called Co-prime if their HCF is 1.

Example: 12 and 25

Factors of 12 are 1, 2, 3, 4, 6 and 12.

Factors of 25 are 1, 5 and 25. Common Factor is 1

∴ HCF is 1

So, 12 and 25 are Co-prime.