1/2+1/3+1/30+1/31+1/41+20/51+10/119+26/120+38/123+27/124的巧算方法!
问题描述:
1/2+1/3+1/30+1/31+1/41+20/51+10/119+26/120+38/123+27/124的巧算方法!
答
1/2+1/3+1/30+1/31+1/41+20/51+10/119+26/120+38/123+27/124 =1/2+1/3+1/30+1/31+1/41+(1/3+1/17)+(1/7-1/17)+(1/4-1/30)+(1/3-1/41)+(1/4-1/31)=1/2+1/3+1/3+1/7+1/4+1/3+1/4=2+1/7=15/7你看看吧!