(5乘7)分之3+(7乘9)分之3+(9乘11)分之3简单算法
问题描述:
(5乘7)分之3+(7乘9)分之3+(9乘11)分之3简单算法
答
(5乘7)分之3+(7乘9)分之3+(9乘11)分之3
=3×½×(1/5-1/7+1/7-1/9+1/9-1/11)
=3/2×(1/5-1/11)
=3/2×6/55
=55分之9怎么感觉没懂