20 7/10, 20 3/4, 18 9/10 , 20 18/25
The denominators are 10, 4, and 25.
You need to find the multiple of each number to get the least common denominator.
multiple of 4: 4, 8, 12, 16, 20, 24, 28,32, 36, 40
44, 48, 52, 56, 60, 64, 68,72, 76, 80
84, 88, 92, 96,100
multiple of 10: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100
multiple of 25: 25, 50, 75, 100
The least common denominator of the 3 numbers is 100.