Answered

Cole has 8 pieces of string that are 5 yards each. He uses 4 pieces that are each 5 feet long.

How many feet of string does Cole have left?



Answer :

100 feet
To find the total length of the entire string you multiply 8 times 5 and get 40.
To convert into feet multiply by 3 and get 120 feet. 
To find the total amount of string he uses, multiply 4 times 5 and get 20. It is already in feet.
Next you subtract 120 - 20 and get 100 feet, the total amount of string he has left.