Write the multiple of 5 and 8
5 = 5, 10, 15, 20, 25, 30, 35, 40,.....
8 = 8, 16, 24, 32, 40, 48, 53,.....
We can observe that 40 is least common multiple in both. So LCM is 40
What is the Lcm of 5/8?
All you have to do is list the multiplies of both of the numbers and look for the common number. (as Deepak has demonstrated)
The LCM for 5/8 is 40.