What is the least common denominator of 20 and 16?

Answer 1

There is none because the Least Common Denominator (or LCD) refers to the Least Common Multiple (LCM) of the denominators of two or more fractions or mixed numbers. Even if you converted your whole numbers (x) to their fraction equivalents (x/1), the LCD would always be 1.

Answer 2

LCM= 80

You can figure the answer out by using a factor tree like the following:

16 20

^ ^

2 x 8 2 x 10

^ ^

2 x 4 2 x 5

^

2 x 2

The bold numbers are the prime numbers so we list them like this:

16= 2 x 2 x 2 x 2 20= 2 x 2 x 5

16 has more 2s than 20 so we take the four 2s from 16 and one 5 from 20.

2 x 2 x 2 x 2 x 5=LCM

LCM=80