计算下面各题(能简算的简算). (1)4/5×3.5+5.5×80%+0.8 (2)11/16+8/13-(11/16-8/13) (3)1/3÷(2/3-2/5)×3/5.

问题描述:

计算下面各题(能简算的简算).
(1)

4
5
×3.5+5.5×80%+0.8    
(2)
11
16
+
8
13
-(
11
16
-
8
13

(3)
1
3
÷(
2
3
-
2
5
)×
3
5

(1)

4
5
×3.5+5.5×80%+0.8    
=(3.5+5.5+1)×0.8
=10×0.8
=8;
(2)
11
16
+
8
13
-(
11
16
-
8
13

=(
11
16
-
11
16
)+(
8
13
+
8
13

=0+
16
13

=1
3
13

(3)
1
3
÷(
2
3
-
2
5
)×
3
5

=
1
3
÷
4
15
×
3
5

=
1
3
×
15
4
×
3
5

=
3
4