能简算的要简算. 2.87+5.6-0.87+4.4 11/18×9-11/18×6 420÷7÷6 9/10-( 1/4+7/20)÷3/4 1/2x+3/5x=4.4(解方程)

问题描述:

能简算的要简算.

2.87+5.6-0.87+4.4  
11
18
×9-
11
18
×6
420÷7÷6    
9
10
-( 
1
4
+
7
20
)÷
3
4
1
2
x+
3
5
x=4.4(解方程)

(1)2.87+5.6-0.87+4.4,
=(2.87-0.87)+(5.6+4.4),
=2+10,
=12;
(2)

11
18
×9-
11
18
×6,
=(9-6)×
11
18

=3×
11
18

=
11
6

(3)420÷7÷6,
=420÷(6×7),
=420÷42,
=10;
(4)
9
10
-(
1
4
+
7
20
)÷
3
4

=
9
10
-
3
5
×
4
3

=
9
10
-
4
5

=
1
10

(5)
1
2
x+
3
5
x=4.4,
  (
1
2
+
3
5
)x=4.4,
      
11
10
x=4.4,
 
11
10
11
10
=4.4÷
11
10

          x=4.4×
10
11

          x=4.