Erica bought 3 1/2 yards of fabric if she uses 2/3 of the fabric how much will she have left?

First, convert 3 1/2 into an improper fraction, which is 7/2. Now, you have to make sure both sides have a common denominator. This will be 6. So now the equation is 21/6 - 4/6. Subtract the numerators, which is 17. Keep the denominator, however. Now, simplify. You new answer will be 2 5/6.