Question

求简便运算，要过程。（能简便的要简便）

7/8-1/4+5/12

2-(1-3/7+4/7)

0.27×7.2－2.7×0.71

﹙9.9＋0.1－9.9＋0.1﹚÷0.01
解方程。

x－5／8＝3／8

5／12＋x＝7／9

x－3／8＋1／9＝4／9

口算

1／6－1／7＝
3／4＋0.5＝

Answer 1

解：（1）7/8-1/4+5/12
=21/24-6/24+10/24
=25/24
（2）2-(1-3/7+4/7)
=2-1+3/7-4/7
=1-1/7
=6/7

（3）0.27×7.2－2.7×0.71
=2.7×0.1×7.2-2.7×0.71
=2.7×(0.72-0.71)
=2.7×0.01
=0.027
（4）﹙9.9＋0.1－9.9＋0.1﹚÷0.01
=0.2÷0.01
=20

（5）x－5／8＝3／8

x=3/8+5/8
x=1
（6）5／12＋x＝7／9

x=7/9-5/12
x=28/36-15/36
x=13/36
（7）x－3／8＋1／9＝4／9
x=4/9-1/9+3/8
x=1/3+3/8
x=8/24+9/24
x=17/24

(8) 1／6－1／7＝1/42
(9) 3／4＋0.5＝5/4

Answer 2

7/8-1/4+5/12=21/24-6/24+10/24=21-6+10/24=25/24

2-(1-3/7+4/7)=2-(7/7-3/7+4/7)=2-(7-3+4/7)=2-8/7=14/7-8/7=14-8/7=6/7

0.27×7.2－2.7×0.71=2.7×0.1×7.2-2.7×0.71=2.7×0.72-2.7×0.71=2.7×(0.72-0.71)=2.7×0.01=0.027

﹙9.9＋0.1－9.9＋0.1﹚÷0.01=﹙9.9－9.9+0.1＋0.1﹚÷0.01=0.2÷0.01=20

Answer 3

能不能不打字啊···