Mandy has 50 yards of fabric to make costumes for a play. she makes 12 skirts that take 3 yards each, and 9 hats that take 1 yard each. which expression represents the number of yards of fabric that are left?

a. 50 - 12³- 9
b. 50 - 3(12+9)
c. 3 * 12 + 9
d. 50 - 3 * 12 - 9

50 yards. You are going to be taking away from that 50, so "50 -" should be part of the expression. This eliminates C.

12 skirts that take 3 yards each means 3 yards * 12 skirts which is 3 * 12. This is being subtracted from 50.
We also want to subtract 9 hats * 1 yard which is 9 * 1 = 9

Our expression will look like this: 50 - 12 * 3 - 9 * 1
or 50 - 12 * 3 - 9, which is D

12 skirts take 3 yards each = 12*3

9 hats take 1 yard each = 9*1

Remainder of yards left:

50 - 12*3 - 9*1

50 - 12*3 - 9      Option D

I hope this helps.