Use the Euclidean Algorithm to find gcd(972, 1220).
The Euclidea Algorith says that gcd(a, b) = gcd(a, b - a). Therefore, gcd(972, 1220) = gcd(972, 248) = gcd(228, 248) = gcd(228, 20) = gcd(8, 20) = gcd(8, 4) = gcd(0, 4) = 4
+135 
