问题 解答题
简便运算.
2
71
+
1
69
)×23+
25
71

5
8
×100+100×
3
8

23
2
3
×3
1
2
+
1
6
+
1
12
+
1
20
+
1
30

200.9×10%+2.009×490+0.2009×5000.
答案

①(

2
71
+
1
69
)×23+
25
71

=

2
71
×23+
1
69
×23
+
25
71

=(

46
71
+
25
71
)+
23
69

=1+

1
3

=1

1
3

5
8
×100+100×
3
8

=100×(

5
8
+
3
8
),

=100×1,

=100;

③23

2
3
×3
1
2
+
1
6
+
1
12
+
1
20
+
1
30

=

71
3
×
7
2
+
1
2
-
1
3
+…+
1
5
-
1
6

=

497
6
+
1
2
-
1
6

=

497
6
+
2
6

=

499
6

=83

1
6

④200.9×10%+2.009×490+0.2009×5000,

=20.09×1+20.09×49+20.09×50,

=20.09×(1+49+50),

=20.09×100,

=2009.

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