А)
1/2+1/3-1/4-1/6 = 6/12 + 4/12 + 3/12 + 2/12 = 15/12 = 5/4 = 1 1/4.
Б)
-1/5+1/6-1/10+1/12 = -12/60 + 10/60 - 6/60 + 5/60 = -3/60 = -1/20.
В)
-3/7-1/3+3/14+1/6 = -18/42 - 14/42 + 9/42 + 7/42 = -16/42 = -8/21.
Г)
1/4-1/16-1/8+1/32 = 16/64 - 4/64 - 8/64 + 2/64 = 6/64 = 3/32