Our answer is 40.

We are asked to work out the least common multiple of 8 and 10.
So what I'm going to do is I'm going to list several multiples of 8 and 10:
8: 8, 16, 24, 32, 40, 48, 56, 64, 72, 80...
10: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100
40 is the smallest number that is a multiple of both 8 and 10.
Therefore, 40 is the LCM of 8 and 10.