Add or subtract the following fractions.  Make sure to put your answer in simplest form. 

  1. 1/2-1/4

  2. 7/9+2/6

  3. 3/7-2/5

  4. 1/3+4/8

  5. 5/6-3/9

  6. 2/3+7/8

  7. 7/12-6/16

  8. 4/7+2/4

  9. 3/5+1/2

  10. 35/50-10/50

  11. Mrs. Vesci's bakery sold 3/6 of a chocolate cake, 1 2/3 of a pumpkin pie and 3 1/3  of a cookie cake.  If each slice is 1/6 of a pie, how many slices were sold?

  12. Find number that is between 2/3 and .66.