1) -2 1/6 + 5 1/4 = -2 2/12 + 5 3/12 = 3 1/12
2) 1,75 + 3 1/12 = 1 3/4 + 3 1/12 = 1 9/12 + 3 1/12=4 10/12 = 4 5/6
3) 5,6 - 4 5/6 = 5 3/5 - 4 5/6 = 5 18/30 - 4 25/30 = 23/30
4) -2,4 - 23/30 = -2 2/5 - 23/30 = -(2 12/30 + 23/30)= -2 35/30 = -3 5/30 = -3 1/6