Question

1/12+1/20+1/30+.........+1/90等于多少

Answer 1

你好，你提的这个问题是一道简单的初中数学题
这道题主要考察简便方法的计算
这道题的解法是
1/12+1/20+1/30+.........+1/90
=1/(3*4)+1/(4*5)+1/(5*6)+.........1/(8*9)+1/(9*10)
=1/3-1/4+1/4-1/5+1/5-1/6+.........1/8-1/9+1/9-1/10
=1/3-1/10
=7/30
希望帮到你，望采纳

Answer 2

1/12+1/20+1/30+.........+1/90
=1/(3*4)+1/(4*5)+1/(5*6)+.........1/(8*9)+1/(9*10)
=1/3-1/4+1/4-1/5+1/5-1/6+.........1/8-1/9+1/9-1/10
=1/3-1/10
=7/30