Can someone me. i need someone fast and hopefully correct.

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.