初中数学题!!!!

来源：百度知道 编辑：UC知道 时间：2024/07/13 03:57:29
偶要步骤!!!!
明白?答对了,我会追加20分
(-0.8)+1.2+(-0.7)+(-2.1)+0.8+3.5=
(-3 1/2)+(4 1/3)+21/2+(-4 2/3)=
(-2 1/5)+8 3/5+3 1/5+(-3 5/7)+(-4 2/7)=
-0.375+3.25+(-5 5/8)+(-1.25)=

(-0.8)+1.2+(-0.7)+(-2.1)+0.8+3.5= -0.8+0.8+(1.2+3.5-2.1-0.7)=0+(4.7-2.8)=1.9

(-3 1/2)+(4 1/3)+21/2+(-4 2/3)= (-31/2+21/2)+(41/3-42/3)=-10/2-1/3=-5-1/3=-16/3

(-2 1/5)+8 3/5+3 1/5+(-3 5/7)+(-4 2/7)= (-21/5+83/5+31/5)+(-35/7-42/7)=93/5-11=38/5

-0.375+3.25+(-5 5/8)+(-1.25)=-3/8+13/4-55/8-5/4=(-3/8-55/8)+(13/4-5/4)=-29/4+8/4=-21/4

晕,不过有20分就好
(-0.8)+1.2+(-0.7)+(-2.1)+0.8+3.5
=0.8-0.8+3.5+1.2-0.7-2.1
=4.7-0.7-2.1
=1.9
(-3 1/2)+(4 1/3)+21/2+(-4 2/3)
=(-7+21)/2 + (13-14)/3
=7+1/3
=7 1/3
哎,不做了,你自己做

1=-5.3