> 数学 >
(1-
1
15
)+(1-
1
35
)+(1-
1
63
)+(1-
1
99
)+(1-
1
143
)+(1-
1
195
)+(1-
1
255
)+(1-
1
323
)+(1-
1
399
)+(1-
1
483
)=______.
人气:395 ℃ 时间:2019-10-05 02:35:51
解答
(1-
1
15
)+(1-
1
35
)+(1-
1
63
)+(1-
1
99
)+(1-
1
143
)+(1-
1
195
)+(1-
1
255
)+(1-
1
323
)+(1-
1
399
)+(1-
1
483

=(1+1+…+1)-(
1
15
+
1
35
+…
1
483

=10-
1
2
×(
1
3
-
1
5
+
1
5
-
1
7
+…+
1
21
-
1
23

=10-
1
2
×(
1
3
-
1
23

=10-
1
2
×
20
69

=10-
10
69

=
680
69

故答案为:
680
69
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