The LCM of 15 and 25 is 75
The LCM is the smallest number that you can get from multiplying both numbers.
multiples of 15: 15, 30, 45, 60, 75...
multiples of 25: 25, 50, 75....
as you can see, 75 is the first number to pop up in both.
Hope this helps! ;D
