问题 解答题
用简便方法计算,并要写出主要的简算过程.
7
11
-
1
5
+
4
11

1
4
×12.5×8×0.4
24×(
3
8
-
1
6
)
×12.
答案

7
11
-
1
5
+
4
11

=

7
11
+
4
11
-
1
5

=1-

1
5

=

4
5

1
4
×12.5×8×0.4,

=(

1
4
×8)×(12.5×0.4),

=2×5,

=10;

24×(

3
8
-
1
6
)×12,

=(24×

3
8
-24×
1
6
)×12,

=(9-4)×12,

=5×12,

=60.

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问答题 简答题