问题 解答题
怎样简便就怎样计算.
5
7
×8-
5
7
8×(
1
16
+
7
8
2
3
×
5
8
+
1
3
×
5
8
答案

5
7
×8-
5
7

=

5
7
×(8-1),

=

5
7
×7,

=5;

8×(

1
16
+
7
8
),

=8×

1
16
+8×
7
8

=

1
2
+7,

=7

1
2

2
3
×
5
8
+
1
3
×
5
8

=(

2
3
+
1
3
)×
5
8

=1×

5
8

=

5
8

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