List the first several nonzero multiples of 24 and 36. The set of nonzero multiples of 24 is {24, 48, 72, 96, 120, 144, . . .}, and the set of nonzero multiples of 36 is {36, 72, 108, 144, . . .}.
Find the first several common multiples of 24 and 36 by taking the intersection of those sets.
{36, 72, 144, . . . }
{48, 72 144, . . . }
{72, 144, . . .
{36, 48, 72, . . . }