1) 2, 1/7 + 1, 6/7 + 6, 4/15 = 4 + 6, 4/15 = 10, 4/15
2) 9, 3/5 - 4, 3/5 - 2, 1/3 = 5 - 2, 1/3 = 2, 2/3
3) 1, 2/13 + 2, 5/9 - 1, 5/9 = 1, 2/13 + 1 = 2, 2/13
4) ошибочка у тебя в примере?
5) 1/11+10/11 + 2/11+9/11 + 3/11+8/11 + 4/11+7/11 + 5/11+6/11 = 1+1+1+1+1 = 5