Question

find the largest number which exactly divides 210,315,147 and 161

Answer 1

Prime factorization of,
210=2×3×5×7

315=3²×5×7

147=3×7²

161=7×23

HCF of 210,315,147 and 161 is the largest number which exactly divides these numbers.
Therefore,
HCF=product of common prime factors of least power.
HCF=7

Hence 7 is the largest number which exactly divides 210,315,147 and 161.

Answer 2

first we have to find its prime factors...
210=2x5x7x3

315=5x3x7x3

147=7x7x3

161=7x23

hcf is7