(-3 1/4)+(-2 3/4)
=-（3 1/4+2 3/4）
=-6
(-1.2)+(+1 1/5)
-(6/5)+6/5
=0
1/3+(- 7/3)
=1/3-7/3
=2
(3 2/7)+(-2 5/7)
=23/7-19/7
4/7
(-1.9)+3.6+(-10.1)+1.4
(3.6+1.4)+[(-1.9)+(-10.1)]
=-7
(-7)+(+11)+(-13)+9
=(11+9)-(13+7)
=0
怎样,初一的,对么