1/6+1/24+1/60+1/120+1/210的简便计算
问题描述：
1/6+1/24+1/60+1/120+1/210的简便计算
答
原式=1/6*[6(1/6+1/24+1/60+1/120+1/210)]
=1/6*[1+1/4+1/10+1/20+1/35]
=1/6*[5/4+3/20+1/35]
=1/6*[28/20+1/35]
=1/6*[200/140]
=100/420
=2/21
答
没有吧.
如果你要答案,还是按部就班地算吧.
1/6+1/24+1/60+1/120+1/210
=140/840+35/840+14/840+7/840+4/840
=200/840=5/21