The GCF is 8.
GCD: 8
The Greatest Common Divisor (GCD) for 56 72 is 8.
56=2*2*2*724=2*2*2*32*2*2=8=GCD
The least common multiple of 24 , 56 , 72 = 504
The greatest common factor of 24, 56 and 72 is 8.
GCD(27, 72) = 9
The greatest common factor of 24 56 and 72 is 8.
The LCM is 8568
gcd(a,b) = greatest common divisor (or factor, whatever) of a and b. For any set of number, a1, a2, a3, ..., you can use the Euclidean algorithm (http://en.wikipedia.org/wiki/Euclidean_algorithm) to get the gcd(a1, a2), and then again to get gcd(gcd(a1, a2), a3), etc. Often, though, you can eyeball it. So 24*3 = 72. Therefore, gcd(24, 72)=24. 24 does not divide 132, but 12 does (the next biggest factor of 24), so gcd(24, 72, 132)=12.
GCD: 9
The Greatest Common Divisor (GCD) for 56 84 is 28.