七年级数学有理数减法简便运算题

1-4/9 =
1-7/10=
8/15-5=
7-15=
2/8-5/8=
8/27-5 =
4-27 =
11/12-10/12=
16/21-1/7 =
4/ 2-(3+3 )=
1/3- 7/12-7/18=
1 -1/3-1 1/5 =
10-7/10=
5/24+3/8 =

乘方,开方等等-1-1=-1^^^^^^^

(-20)+(+3)-(-5)+(-7)
=-20+3+5-7
=-19
-7-5-4-10
=-12-4-10
=-26

1+1=2