a box of thread weighs 8 pounds. if each spool of thread weighs ½ pound, how many spools of thread are in the box?
a. 8 spools
b. 10 spools
c. 12 spools
d. 16 spools

The answer to your question is D
.5 x 8= 4 pounds
.5 x 10=5 pounds
.5 x 12=6 pounds
.5 x 16=8 pounds

In order to find out how many spools of threads are in the box, take the weight of the box, and divide it by how much each spool weighs:

8 divided by 1/2 < this is your equation. When dividing fractions, you keep the first value (8), switch the operation (so instead of dividing, you are now multiplying) and you flip the second value (1/2 becomes 2/1). Your new equation should be:

8 (or 8/1) x 2/1 which is basically saying 8 x 2, which equals 16. 

There are 16 spools of thread in the box. 

Subtracting is the opposite of adding