jmc

Question

Find the greatest common divisor of 7! and (5!)^2.

Accepted Answer

arrayrcrcr 7! &=& 7 6 5 4 3 2 1 &=& 2^4 3^2 5^1 7^1 (5!)^2 &=& (5 4 3 2 1)^2 &=& 2^6 3^2 5^2 gcd(7!, (5!)^2) &=& 2^4 3^2 5^1 &=& 720 array