The LCM (or the least common multiple) of 3, 7, and 2 can be solved like so.
What is the lowest number that are multiples (products in multiplication) of 3, 7, and 2.
Heres an easy method to do it (To find if a number is a multiple of three, add together the digits and if it can be divided by 3, then its a multiple)
7 * 2 = 14 (Multiple of 2 but not 3)
7 * 3 = 21 (Multiple of 3 but not 2)
7 * 4 = 28 (Multiple of 2 but not 3)
7 * 5 = 35 (None)
7 * 6 = 42 (Multiple of both 2 and 3)
The Answer is 42