1.(--3又5/6)+(2又2/5)-(+2又1/6-(-7又3/5)
=(-3+2-2+7)+(-5/6+2/5-1/6+3/5)
=4+0=4
2、(-0.6)-(-3又1/4)-(+7又2/5)+2又3/4
=-0.6+3.25-7.4+2.75
=-8+6=-2
3.-9.2-(+7.1)-(-3)+6又1/5+(-2.9)
=-(9.2+7.1-3-6.2+2.9)
=-(9.2-6.2-3+7.1+2.9)
=-(3-3+10)=-10
4.12又1/4-1.75+5又1/2-7.25+2又3/4-2.5
=12.25-1.75+5.5-7.25+2.75-2.5
=(12.25-7.25)+(2.75-1.75)+(5.5-2.5)
=5+1+3=9
5.2/5-|-1/2|-(+2又1/4)-(-2.75)
=0.4-0.5-2.25+2.75
=0.4+(2.75-2.75)
=0.4=2/5