问题 解答题
怎样简便就怎么算.
5
4
÷(
5
4
÷
15
4
)

(
5
6
+
11
12
11
12

(
5
8
-
1
3
×
5
4
)×24

5
7
×21+
2
7
÷
1
21
答案

(1)

5
4
÷(
5
4
÷
15
4
),

=

5
4
÷
1
3

=

15
4

(2)(

5
6
+
11
12
11
12

=(

5
6
+
11
12
)×
12
11

=

5
6
×
12
11
+
11
12
×
12
11

=

10
11
+1,

=1

10
11

(3)(

5
8
-
1
3
×
5
4
)×24,

=(

5
8
-
5
12
)×24,

=

5
8
×24-
5
12
×24,

=15-10,

=5;

(4)

5
7
×21+
2
7
÷
1
21

=

5
7
×21+
2
7
×21,

=(

5
7
+
2
7
)×21,

=1×21,

=21.

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