What is the least common multiple of 3 and 8 with prove?

Answer 1

24.

A multiple of (x), for example, is a number divisible by x.

So multiples of 3 are 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48 ...etc.

Multiples of 8 are 8, 16, 24, 32, 40, 48 ...etc.

Since the lowest multiple which 3 and 8 have in common is "24", it is called the "LCM" (a.k.a. Lowest Common Multiple). 48 is a common multiple shared by 3 and 8, but it is not the lowest.

This is essentially a mathematical / analytical proof, so I hope it helps.