What is a greatest common multiple

The greatest common multiple the the largest integer that can go into two other integers.
For example.
60 and 75. A common multiple would be five since it can got into both evenly. However, the largest common multiple would be 15, because it is the largest whole number that can go into 60 and 75.
Just in case, an integer is a whole number. No decimals.

Ithink the answer is $2.10