问题 解答题
怎样简便就怎样算.
(1)3-
7
12
-
5
12
(2)
5
7
×
3
8
+
5
8
×
5
7
(3)
8
15
×
5
16
+
5
27
÷
10
9
(4)18×(
4
9
+
5
6
(5)(
5
7
×
4
7
+
4
7
)÷
4
7
(6)
1
5
÷[(
2
3
+
1
5
)×
1
13
].
答案

(1)3-

7
12
-
5
12

=3-(

7
12
+
5
12
),

=3-1,

=2;

(2)

5
7
×
3
8
+
5
8
×
5
7

=(

3
8
+
5
8
)×
5
7

=1×

5
7

=

5
7

(3)

8
15
×
5
16
+
5
27
÷
10
9

=

8
15
×
5
16
+
5
27
×
9
10

=

1
6
+
1
6

=

1
3

(4)18×(

4
9
+
5
6
),

=18×

4
9
+18×
5
6

=8+15,

=23;

(5)(

5
7
×
4
7
+
4
7
)÷
4
7

=(

5
7
×
4
7
+
4
7
)×
7
4

=

5
7
×
4
7
×
7
4
+
4
7
×
7
4

=

5
7
+1,

=1

5
7

(6)

1
5
÷[(
2
3
+
1
5
)×
1
13
],

=

1
5
÷[
13
15
×
1
13
],

=

1
5
÷
1
15

=

1
5
×15,

=3.

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