问题 解答题
计算
1
42
+(
5
8
-
5
12
)×
4
5
(1-
1
2
×
7
4
)÷
10
11
4
7
×
1
4
+25%×
3
7
8
9
×[
3
4
-(
7
16
-
1
4
)].
答案

(1)

1
42
+(
5
8
-
5
12
)×
4
5

=

1
42
+
5
8
×
4
5
-
5
12
×
4
5

=

1
42
+
1
2
-
1
3

=

11
21
-
1
3

=

4
21

(2)(1-

1
2
×
7
4
)÷
10
11

=(1-

7
8
)÷
10
11

=

1
8
÷
10
11

=

11
80

(3)

4
7
×
1
4
+25%×
3
7

=25%×(

4
7
+
3
7
),

=25%×1,

=25%;

(4)

8
9
×[
3
4
-(
7
16
-
1
4
)],

=

8
9
×[
3
4
-
3
16
],

=

8
9
×
9
16

=

1
2

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