What is the lowest common demoninator of 1/3, 1/5, 1/20, and 1/50?

... 1?

3, 5, 20, 50 = \frac{3}{1}, \frac{5}{1}, \frac{20}{1}, \frac{50}{1}

all of these have the same denominator, 1.

Are you sure you don't mean Least Common Multiple?

What is the lowest common demoninator of 1/3, 1/5, 1/20, and 1/50?
jallen26: Do you mean Least Common Multiple (LCM)?

Are you sure you don't mean Least Common Multiple?.

I asked the wrong question... I meant 1/3, 1/5, 1/20, and 1/50.

Find the least common multiple of the denominators
Start with one pair and then add the next one in
1/(LCM(3,LCM(5,LCM(20,50))))