Answer:
The LCM (least common multiple) of two numbers is the smallest number (different from zero) that is a multiple of both.
So, we need to find 2 numbers different from 28 that have 28 as a multiple and it has to be the least one, so this numbers must be smaller than 28.
If we look into all the numbers smaller than 28 that have 28 as a multiple we find: 2, 4, 7 and 14
The only 2 that have the LCM 28 are 4 and 7.
Explanation: