3/7 + 4/9, 8/9 - 7/8, 13/15 - 2/3, 20/21 + 3/7, 17/18 - 11/12, 7/16 + 1/6, 2/9 + 5/6, 10/21 + 9/14, 7/9 - 4/15, 9/14 -3/7 + 15/28, 1/6 + 1/4 - 1/8, 13/18 - 29/45 +8/15
Б СРОЧНООООООО!!!!!!!!!!!!!!!ПОМОГИТЕ