-21.6+3-7.4+(-2/5)(-6/5)-7-(-3.2)+(-1)

问题描述:

-21.6+3-7.4+(-2/5)
(-6/5)-7-(-3.2)+(-1)

1)=-21.6+3-7.4-0.4=-26.4
2)-1.2-7+3.2-1=-6

-21.6+3-7.4-0.4
=(-26.4)
-1.2-7+3.2-1
=(-6)

-21.6+3-7.4+(-2/5)
=-21.6-7.4+3-0.4
=-(21.6+7.4)+3-0.4
=-29+3-0.4
=-26.4
(-6/5)-7-(-3.2)+(-1)
=-1.2-7+3.2-1
=(3.2-1.2)-7-1
=2-7-1
=-6