7) 1,1/2 - 2,1/4 = 1 + 1/2 - 2 + 1/4 = -1/2
8) 3,1/3 - 4,1/6 = 3 + 1/3 - 4 - 1/6 = -1,1/2
9) 2,1/16 + 5,1/4 = 2 + 1/16 + 5 + 1/4 = 7,5/16
7) 1,1/2 - 2,1/4 = 1 + 1/2 - 2 + 1/4 = -1/2
8) 3,1/3 - 4,1/6 = 3 + 1/3 - 4 - 1/6 = -1,1/2
9) 2,1/16 + 5,1/4 = 2 + 1/16 + 5 + 1/4 = 7,5/16