1 -2又1/4+-2/3+-5又3/4+2/3=(-2又1/4+-5又3/4)+(-2/3+2/3)
=-8+0
=-8
2 [(三又三十七分之十五)+(负九点五)+(负十二又三十分之十)] +【(负三十七分之五)+(+十又二分之一)
=3又15/37+-5/37+-12又10/30+(10又1/2+-9又1/2)
=3又10/37-12又10/30+1
=3又300/1110-12又370/1110+1
=-9又70/1110+1
-9又7/111+1
3 0-1/2--1/3--1/4-1/6
=0-1/2+1/3+1/4-1/6
=-3/6+2/6-1/6+1/4
=-2/6+1/4
=-1/3+1/4
=-1/12