问题 解答题
计算.
(1-
3
4
)÷(1+
1
4
)
(
3
4
-
1
3
)÷(
11
15
-
2
5
)
2.8×
5
2
÷(
3
10
×12)
18×
5
9
-16.2÷3
答案

(1)(1-

3
4
)÷(1+
1
4

=

1
4
÷
3
4

=

1
4
×
4
3

=

1
3

(2)(

3
4
-
1
3
)÷(
11
15
-
2
5

=

5
12
÷
1
3

=

5
12
×3

=

5
4

(3)2.8×

5
2
÷(
3
10
×12)

=7÷

18
5

=7×

5
18

=

35
18

(4)18×

5
9
-16.2÷3

=10-5.4

=4.6.

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