Question

Ben has 1/2 pound of modeling clay. He used 1/5 of a pound on Monday. He used 1/4 pound on Tuesday. How many pound of clay does Ben have left after Tuesday?

Answer 1

The first thing you want to do is make all of them have a common denominator

1/2 = 10/20
1/4 = 5/20
1/5 = 4/20
you then do 10/20 - 5/20 - 4/20

the final answer is 1/20 pounds of clay

Answer 2

Change the fractions to decimals for as easy algebraic solution.

.5 - (.2 + .25) = .05. Only 1/10 of the clay is left.