The first 3 multiples of 4 are: 4, 8, and 12.The first 3 multiples of 5 are: 5, 10, and 15.
20 is the smallest common multiple of 4, 5, and 10, and thus the first. Thus, the first three common multiples of 4, 5, and 10 are 20, 40 and 60.
The first 4 multiples of three are:3x13x23x33x4
20, 40, 60
40, 80, 120
The first three multiples of 4 are 4, 8 and 12. For them to be common, they need to be compared to another set of multiples.
They are: 40 80 and 120
20, 40, 60
40, 80, 120
40, 80, 120
20, 40, 60
40, 80 ,120.