问题 解答题
用递等式计算.
0.625×(8.3-2.5×0.12)
3
7
-
3
7
÷3
9
20
÷[
1
2
×(
2
3
+
4
5
)].
答案

0.625×(8.3-2.5×0.12),

=0.625×(8.3-0.3),

=0.625×8,

=5;

3
7
-
3
7
÷3,

=3×

7
3
-
3
7
×
1
3

=7-

1
7

=6

6
7

9
20
÷[
1
2
×(
2
3
+
4
5
)],

=

9
20
÷[
1
2
×
22
15
],

=

9
20
×
15
11

=

27
44

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