问题 解答题
简便方法计算.
(
3
7
+
3
28
)×7
3
5
×63%+
7
5
×63%
5.2×
1
4
+1.8×0.25
答案

(1)(

3
7
+
3
28
)×7

=

3
7
×7+
3
28
×7

=3+

3
4

=3

3
4

(2)

3
5
×63%+
7
5
×63%

=(

3
5
+
7
5
)×63%

=2×0.63

=1.26;

(3)5.2×

1
4
+1.8×0.25

=(5.2+1.8)×0.25

=7×0.25

=1.75.

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