(1/3-7/12+9/20-11/30+13/42-15/56)×2的三次方
=(1/3-1/3-1/4+1/4+1/5-1/5-1/6+1/6+1/7-1/7-1/8)×8
=-1/8×8
=-1
解:将题干以数学形式呈现如下:
(1/3-7/12+9/20-11/30+13/42-15/56)*(-2)^3
=(4/12-7/12+27/60-22/60+104/336-90/336)*(-8)
=(-3/12+5/60+14/336)*(-8)
=(-1/3+1/12+1/24)*(-8)
=-3/24*(-8)
=-1/8*(-8)
=1