11,5 * (-2/7)+ 13: 5 - 6 целых 2/5 !

11,5 * (-2/7) + 13 : 5 - 6 2/5 = -16 8/15,

1) 11,5 * (-2/7) = -115/10 * 2/7 = -23/7 = - 3 2/7,
2) 13 : 5 = 13/5 = 2 3/5,
3) -3 2/7 + 2 3/5 - 6 2/5 = -23/7 + 13/5 - 32/5 = -23/7 - 19/5 = -115/35 - 133/35 = -248/15 = - 16 8/15