Euclidean algorithm
A procedure for computing \gcd(a,b) by repeated division: replace (a,b) with (b,r), the divisor and remainder from dividing a by b, until the remainder reaches 0 -- the last nonzero remainder is the gcd.
Examples
Finding \gcd(48,18): 48=2(18)+12, 18=1(12)+6, 12=2(6)+0, so \gcd(48,18)=6.
See also
Point table
Graph settings
Calculator