南京到井冈山红色路线:巧算 1/30+1/42+1/56+1/72+1/90
来源:百度文库 编辑:高校问答 时间:2024/10/06 16:14:08
=1/5*1/6+1/6*1/7+1/7*1/8+1/8*1/9+1/9*1/10
=(1/5-1/6)+(1/6-1/7)+(1/7-1/8)+(1/8-1/9)+(1/9-1/10)
=1/5-1/10
=1/10
如何巧算最快呢?
就是将你这一串 复制到 百度搜索输入框中,然后得到答案是:
1/30+1/42+1/56+1/72+1/90 = 0.1
巧算 1/30+1/42+1/56+1/72+1/90
1/30+1/42+1/72+1/90+…1/9900
30/1+42/1+56/1+72/1+90/1=?
20/1+30/1+42/1+56/1+72/1+90/1
1/20+1/30+1/42+1/56+1/72+1/90
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=?
有一列数:1/2,1/6,1/12,1/20,1/30,1/42……
1/22+1/30+1/42+1/56+1/72+1/90=?简便方法是什么?
谁能巧算1-1/2-1/6-1/12-1/20-1/30-1/42-1/56-1/72-1/90