subtract fractions

recca · #1 $Old$ May 9th, 2008, 08:40 AM

Can the following story problems about a bird feeder be solved by subtracting 3/4-1/2? If so, explain why. If not, explain why not and solve the problems if they can be solved. Write a different story problem about a bird feeder that can be solved by subtracting 3/4-1/2.

Story problem 1 about a bird feeder: A bird feeder was filled with 3/4 of a full bag of bird seed. The birds ate 1/2 of what was in the bird feeder. What fraction of a full bag of bird seed did the birds eat?

Story problem 2 about a bird feeder: A bird feeder was filled was 3/4 of a full bag or bird seed. The birds ate 1/2 of what was in the bird feeder. What fraction of a full bag of bird seed is left in the bird feeder?

Thank you

blair_alane · #2 $Old$ May 9th, 2008, 09:00 AM

Quote:

Originally Posted by recca $View Post$

Story problem 1 about a bird feeder: A bird feeder was filled with 3/4 of a full bag of bird seed. The birds ate 1/2 of what was in the bird feeder. What fraction of a full bag of bird seed did the birds eat?

So...they ate 1/2 of the 3/4 of the bag? You would have to multiply 3/4 and 1/2.... so... $\frac{3}{4}\cdot\frac{1}{2}=\frac{3}{8}$ of the bag.

Quote:

Story problem 2 about a bird feeder: A bird feeder was filled was 3/4 of a full bag or bird seed. The birds ate 1/2 of what was in the bird feeder. What fraction of a full bag of bird seed is left in the bird feeder?

Now you just subtract that amount from one.
$\frac{8}{8}-\frac{3}{8}=\frac{5}{8}$ left.

I hope that's right!

Sorry if it's not....