8+89+899+8999+89999+899999
=?
maths
2007-12-21 12:43 am
回答 (6)
2007-12-21 12:47 am
2007-12-21 6:32 am
8+89+899+8999+89999+899999=999,993
2007-12-21 3:41 am
8+89+899+8999+89999+899999
= (10-2) + (100-11) + (1000-101) + (10000-1001) + (100000-10001) + (1000000-100001)
= (10-2) + (100-10-1) + (1000-100-1) + (10000-1000-1) + (100000-10000-1) + (1000000-100000-1) ....... 每個括號內的第一項可與隨後的括號內的第二項相抵銷
= -2 + (-1) + (-1) + (-1) + (-1) + (1000000-1) ........ 所以只剩每個括號的最後一項和最後一個括號的第一項(及最後一項)
= 1000000 - 7
= 999993
= (10-2) + (100-11) + (1000-101) + (10000-1001) + (100000-10001) + (1000000-100001)
= (10-2) + (100-10-1) + (1000-100-1) + (10000-1000-1) + (100000-10000-1) + (1000000-100000-1) ....... 每個括號內的第一項可與隨後的括號內的第二項相抵銷
= -2 + (-1) + (-1) + (-1) + (-1) + (1000000-1) ........ 所以只剩每個括號的最後一項和最後一個括號的第一項(及最後一項)
= 1000000 - 7
= 999993
2007-12-21 1:01 am
8+89+899+8999+89999+899999
=999993
or
(8+80)+(800+8000)+(80000+800000)+9+99+999+9999+99999
=(88+88000)+8800000+111105
=(88088+8800000)+ 111105
=8888088+111105
=999993
=999993
or
(8+80)+(800+8000)+(80000+800000)+9+99+999+9999+99999
=(88+88000)+8800000+111105
=(88088+8800000)+ 111105
=8888088+111105
=999993
2007-12-21 12:49 am
8+89+899+8999+89999+ 899999=999993
***Hope I Can Help You***
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2007-12-21 12:46 am
8+89+899+8999+89999+899999
=?
?=999993
=?
?=999993
收錄日期: 2021-04-24 07:58:32
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071220000051KK01865