小三數學題一條

2007-05-16 1:26 am
1.1+2+3+......+98+99

回答 (12)

2007-05-16 1:30 am
✔ 最佳答案
{(1+99)*99} / 2
= 4950

頭加尾乘項數除二
2007-05-25 4:55 am
I thing it's~4950
參考: me
2007-05-23 5:47 am
(1+99)x99/2
=4950
參考: me
2007-05-23 3:00 am
100x2/2
=4950

2007-05-22 19:01:17 補充:
100x99/2=4950

2007-05-22 19:01:49 補充:
100x99/2=4950
2007-05-19 5:44 am
將佢當成個梯形,

梯形面積係:(上底+下底)x高/2

咁呢題數既上底就係1,下底係99

因為你要加99個數,

所以高就係99

算式就係:

(1+99)x99/2

=100x99/2

=4950

答:4950
參考: 自己專心上課聽老師講既~
2007-05-16 1:49 am
1+2+3+......+98+99 =17701
參考: me
2007-05-16 1:40 am
= [(1+99)/2] *99
= 4950


*第1個數加最尾果個數,再除2, 再乘以項數
2007-05-16 1:39 am
其實計呢條數係有口訣GE 就係:首項加尾項 乘項數 除二

所以

1+2+3+...+98+99

= (1+99)x99/2

= 4950
2007-05-16 1:35 am
= [(1+99)/2] *99
= 4950


*頭加尾除以2, 再乘以項數*
2007-05-16 1:31 am
no. 1= 4950


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