(1)22+(-3)+(-31)+9+(-5)答案为:-8 求过程
=22-3-31+9-5
=22+9-3-31-5
=31-31-5-3
=-5-3
=-8
(2)(+6)+(-12)+8.3+(-7.4)+(+9.1)+(-2.5)答案为:1.5求过程
=6-12+8.3-7.4+9.1-2.5
=-6+8.3+9.1-7.4-2.5
=-6+17.4-7.4-2.5
=-6+10-2.5
=4-2.5
=1.5
(3)(-3/5)+(-1/2)+1/4+(-7/10)答案为:-31/20求过程
=-3/5-1/2+1/4-7/10
=-3/5-1/2-7/10+1/4
=-6/10-5/10-7/10+1/4
=-18/10+1/4
=-9/5+1/4
=-36/20+5/20
=-31/20
(4)(-8.25)+8.75+(-5又1/4)+(-9又1/2)答案为:-14.25求过程
=-8.25+8.75-5.25-9.5
=-8.25-5.25-9.5+8.75
=-13.5-9.5+8.75
=-23+8.75
=-14.25
(5)(-7.34)+(-12.74)+7.34+12.4答案为:-0.34求过程
=-7.34-12.74+7.34+12.4
=7.34-7.34-12.74+12.4
=-12.74+12.4
=-0.34
(6)(-2又1/3)+(+3又1/2)+(-2又2/3)+6又1/2+(-5又3/4)答案为;-3/4求过程
=(-2又1/3)+(+3又1/2)+(-2又2/3)+6又1/2+(-5又3/4)
=-2-1/3+3+1/2-2-2/3+6+1/2-5-3/4
=-2+3-2+6-5-1/3+1/2-2/3+1/2-3/4
=6+3-2-2-5-1/3-2/3+1/2+1/2-3/4
=-(1/3+2/3)+(1/2+1/2)-3/4
=-1+1-3/4
=-3/4
(7)(-1)+(-2)+(-3)+(-4)+……+(-39)+(-40)
=-1-2-3-4+……-39-40
=(-1-40)*40/2
=-820