What is the least common denominator of the four fractions listed below 20 7/10, 20 3/4, 18 9/10, 20 18/25

So what you do is see all the denomenators and factor them (denomenaotrs are the bottom numbres)

10,4,10,25
10=2 times 5
4=2 times 2
10=2 times 5
25=5 times 5
we need to include all of them so we need at leas two 2's, and two 5's
2 times 2 times 5 times 5=100
leact common denomator is 100