问题 解答题
计算下列各题.
860-560÷8×7(5.9+1.65)÷2.5
3
4
+
4
5
)×20÷
31
21
3
5
÷[(
7
9
+
1
3
)×
3
2
].
答案

860-560÷8×7

=860-70×7,

=860-490,

=370;

(5.9+1.65)÷2.5

=7.55÷2.5,

=3.02;

3
4
+
4
5
)×20÷
31
21

=(

3
4
×20+
4
5
×20)÷
31
21

=(15+16)×

21
31

=31×

21
31

=21;

3
5
÷[(
7
9
+
1
3
)×
3
2
].

=

3
5
÷[
10
9
×
3
2
],

=

3
5
÷
5
3

=

9
25

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