问题 解答题
用合适的方法计算下列各题:
5
6
×
12
21
×
7
15
(1+
3
8
)×12
7
16
×32+32×
9
16
4
7
×
7
12
÷
4
9
5
8
÷
3
4
×
9
25
8
17
×8+
8
17
÷8.
答案

5
6
×
12
21
×
7
15

=

2
3
×
1
3

=

2
9

(1+

3
8
)×12

=1×12+

3
8
×12,

=12+

9
2

=12+4

1
2

=16

1
2

7
16
×32+32×
9
16

=(

7
16
+
9
16
)×32,

=1×32,

=32;

4
7
×
7
12
÷
4
9

=

1
3
×
9
4

=

3
4

5
8
÷
3
4
×
9
25

=

5
8
×
4
3
×
9
25

=

1
2
×
3
5

=

3
10

8
17
×8+
8
17
÷8

=

64
17
+
8
17
×
1
8

=3

13
17
+
1
17

=3

14
17

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