How to subtract fractions?

Question

Matthew has 3/4 of a pizza left after going to a local restaurant. Today he eats 1/3 of the remaining pizza for lunch. How much of the original pizza does Matthew have left now?

Answer 1

This is so very clear using a computer with pictures.  Soon, that will be available to all students !

 

Imagine a pizza cut into 4 equal parts (1/4 of pizza each) and 1 is eaten and 3 are left.   ("Matthew has 3/4 of a pizza left after going to a local restaurant.").

 

Today he eats 1 of the 3 (1/3) pieces he brought home.  ("Today he eats 1/3 of the remaining pizza for lunch.).

 

Now he has 2 of the original 4 pieces (that's 1/2).   ("How much of the original pizza does Matthew have left now?").

 

You don't have to eat pizza, you could do this with papers, books, socks, candies, knives (but don't cut yourself), and fingers and toes and siblings and other students and lots of other things ....   (be creative!)

Answer 2

1/3 of 3/4 is 1/3*3/4 = 1/4

 

So, if he eats 1/4 of pizza out of 3/4, he is left with 3/4 -1/4 = 2/4 = 1/2 of the original pizza