问题 解答题
计算
(1)(
48
+
20
)-(
12
-
5

(2)
1
2
3
÷
2
1
3
×
1
2
5

(3)
3a
2b
•(
b
a
÷2
1
b
)

(4)(3
5
)2-(5
3
)2

(5)(
5
+6)(3-
5
答案

(1)原式=(4

3
+2
5
)-(2
3
-
5

=4

3
+2
5
-2
3
+
5

=2

3
+3
5

(2)原式=

15
3
÷
21
3
×
35
5
=
5
7
×
35
5
=1;

(3)原式=

3a
2b
×(
ab
a
÷
2
b
b
)=
3a
2b
×
b
a
2a
=
3
4

(4)原式=45-75=-30;

(5)原式=3

5
-5+18-6
5
=13-3
5

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