(1又3/4-7/8-7/12)÷(-7/8) +(-8/3)=(7/4-7/8-7/12)×(-8/7) -8/3=-(7/4×8/7-7/8×8/7-7/12×8/7) -8/3=-(2-1-2/3)-8/3=-1/3-8/3=-3
