請問以下問題怎樣計算?(列明部驟!!!)解釋!!
1. 11+12+13+14+15+16+15+14+13+12+11
2. 13+16+19+22+25+28
Please help!!!
數學的問題 10分!
2007-03-22 4:17 am
回答 (6)
2007-03-22 4:46 am
✔ 最佳答案
1. 11+12+13+14+15+16+15+14+13+12+11=2*(11+12+13+14+15+16)-16
=2*{6(11+16)]/2}-16
=6(11+16)-16
=162-16
=146
-------------------------------------------------------------------------
2. 13+16+19+22+25+28
=[(13+28)*6]/2
=(41*6)/2
=246/2
=123
***在計算這種題目時,
一般不會將數逐個加上,
而是會用到一條公式,
[(首項+末項)*項數]/2
就以第二題為例
13+16+19+22+25+28
首項是13,
末項是28,
而項數是6,
因此有,
13+16+19+22+25+28
=[(13+28)*6]/2
=123
2007-03-23 3:28 am
1. 11+12+13+14+15+16+15+14+13+12+11
=(12+13+15)+(14+11)+X2+16
=40+25X2+16
=65X2+16
=130+16
=146
====================================
2.13+16+19+22+25+28
=(28+22)+(25+16+19)+13
=50+60+13
=123
=(12+13+15)+(14+11)+X2+16
=40+25X2+16
=65X2+16
=130+16
=146
====================================
2.13+16+19+22+25+28
=(28+22)+(25+16+19)+13
=50+60+13
=123
參考: nth(nothing)
2007-03-22 6:37 pm
1. 11+12+13+14+15+16+15+14+13+12+11
= 11+12+13+14+15x2+16
2.13+16+19+22+25+28
=13x6+3x5
= 11+12+13+14+15x2+16
2.13+16+19+22+25+28
=13x6+3x5
2007-03-22 6:36 pm
1.11+12+13+14+15乘2+16
2.13乘6+3乘5
2007-03-22 10:38:28 補充：
答案:1.1462.93
2.13乘6+3乘5
2007-03-22 10:38:28 補充：
答案:1.1462.93
2007-03-22 4:27 am
1. 11+12+13+14+15+16+15+14+13+12+11
=23+13+14+15+16+15+14+13+12+11
=36+14+15+16+15+14+13+12+11
=50+15+16+15+14+13+12+11
=65+16+15+14+13+12+11
=81+15+14+13+12+11
=96+14+13+12+11
=110+13+12+11
=123+12+11
=135+11
=146
2. 13+16+19+22+25+28
=29+19+22+25+28
=48+22+25+28
=70+25+28
=95+28
=123
=23+13+14+15+16+15+14+13+12+11
=36+14+15+16+15+14+13+12+11
=50+15+16+15+14+13+12+11
=65+16+15+14+13+12+11
=81+15+14+13+12+11
=96+14+13+12+11
=110+13+12+11
=123+12+11
=135+11
=146
2. 13+16+19+22+25+28
=29+19+22+25+28
=48+22+25+28
=70+25+28
=95+28
=123
收錄日期: 2021-05-03 13:07:05
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070321000051KK03688