1+2+3+4+5+6+7+8+9...................................+100
=??
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一題數學題
2007-11-19 1:31 am
回答 (4)
2007-11-19 1:36 am
✔ 最佳答案
(首項+末項) x 項數 / 2=(1 + 100) x 100 / 2
= 5050
2007-11-24 09:26:56 補充：
同樣地，[(首項加末項) x 項數]除2，(2 200)x 100 / 2 = 10100。其實呢，所謂「另一題」只係等於 (1 2 3 4 5 6 7 8 9 ... 100 ) x 2......
2007-11-19 2:15 am
1+2+3+4+5+6+7+8+9...................................+100
=1+100
=2+99
=3+98
=4+97......
=101x50
=5050
=1+100
=2+99
=3+98
=4+97......
=101x50
=5050
2007-11-19 1:49 am
1+100=101
2+99=101
3+98=101
4+97=101
...
50+51=101
101*50=5050
2+99=101
3+98=101
4+97=101
...
50+51=101
101*50=5050
2007-11-19 1:42 am
1+2+3+4+5+6+7+8+9...................................+100
=100x(1+100)除2
=100x101除2
=10100除2
=5050
====
=100x(1+100)除2
=100x101除2
=10100除2
=5050
====
參考: 我中4 la
收錄日期: 2021-04-13 14:32:07
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071118000051KK03355