1/2 - (+4) = 1/2 - 4 = -7/2

5/11 - (-5/1) = 5/11 + 5 = 5/11 + 55/11 = 60/11 = 5 5/11

Итак, -7/2 - 5 5/11 = -7/2 - 60/11 = -77/22 = -3 11/22.