1+2+3+4+5.............................................+100
2007-12-27 5:59 pm
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50+51+52+53+54+55+56+57+58+59+60+61+62+63+64+65+66+67+68+69+70+71+72+73+74+75+76++77+78+79+80+81+82+83+84+85+86+87+89+90+91+92+93+94+95+96+97+98+99+100=???????????.
回答 (8)
2007-12-27 6:15 pm
✔ 最佳答案
我俾條公式你比如1+2+3+4+5.............................................+100
公式:(1+100)*(100/2)
=5050
其他都係咁計
例如1+2+3+4+5.............................................+500
放進公式就是:(1+500)*(500/2)
=125250
從以上例子可知公式係:(1+最大的數)*(最大的數/2)
順便一提(怕你唔知):*=乘， /=除
參考: 自己
2007-12-30 8:44 pm
5050
(頭 + 尾) * (總頂數 / 2)
(1+100)X100
------------------
2
(頭 + 尾) * (總頂數 / 2)
(1+100)X100
------------------
2
2007-12-28 9:38 pm
(頭 + 尾) * (總頂數 / 2)
==>(1 + 100) * (100 / 2)
==>5050
==>(1 + 100) * (100 / 2)
==>5050
2007-12-27 7:16 pm
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50+51+52+53+54+55+56+57+58+59+60+61+62+63+64+65+66+67+68+69+70+71+72+73+74+75+76++77+78+79+80+81+82+83+84+85+86+87+89+90+91+92+93+94+95+96+97+98+99+100=5050
2007-12-27 6:29 pm
Sum of AP: S(n) = (n/2)[2a+(n-1)d]
First team a = 1
Common Difference d = 1
S(100) = (100/2)[2(1) + (100-1)1] = 5050
簡單o黎講
1+2+......+n = n(n+1)/ 2
因為
2*(1+2+3+......+100)
= (1+2+3+.....+100) + (100+99+98+....+1)
= (1+100) + (2+99) + (3+98) + ...... + (100+1)
= 100 * 101
= 10100
所以
1+2+3+......+100 = 10100/2 = 5050
First team a = 1
Common Difference d = 1
S(100) = (100/2)[2(1) + (100-1)1] = 5050
簡單o黎講
1+2+......+n = n(n+1)/ 2
因為
2*(1+2+3+......+100)
= (1+2+3+.....+100) + (100+99+98+....+1)
= (1+100) + (2+99) + (3+98) + ...... + (100+1)
= 100 * 101
= 10100
所以
1+2+3+......+100 = 10100/2 = 5050
參考: 自己
2007-12-27 6:16 pm
1................100=100*50+50=5050
2007-12-27 6:04 pm
超簡單....跟住以下呢個方法唔洗用計數機
1+2+3+4+5+6+7+8+9+10=55
咁11+12+13+14+15+16+17+18+19+20=155
即係21+22+23+24+25+26+27+28+29+30=255
所以31+32+33+34+35+36+37+38+39+40=355
即係55+155+255+355+455+555+655+755+855+955=5050
1+2+3+4+5+6+7+8+9+10=55
咁11+12+13+14+15+16+17+18+19+20=155
即係21+22+23+24+25+26+27+28+29+30=255
所以31+32+33+34+35+36+37+38+39+40=355
即係55+155+255+355+455+555+655+755+855+955=5050
2007-12-27 6:01 pm
is 5050
收錄日期: 2021-04-16 22:08:08
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071227000051KK00777