1/12+1/20+1/30+1/42+.+1/9900等于多少?

来源：学生作业帮助网编辑：作业帮时间：2024/05/07 03:30:37

1/12+1/20+1/30+1/42+.+1/9900等于多少?
1/12+1/20+1/30+1/42+.+1/9900等于多少?

1/12+1/20+1/30+1/42+.+1/9900等于多少?
1/12+1/20+1/30+1/42+.+1/9900
=1/(3*4)+1/(4*5)+1(5*6)+...+1/(99*100)
=1/3-1/4+1/4-1/5+1/5-1/6+...+1/98-1/99+1/99-1/100
=1/3-1/100
=97/300

=（1/3-1/4）+（1/4-1/5）+……+（1/99-1/100）=1/3-1/100=97/300

1/12+1/20+1/30+1/42+.......+1/9900=1/3*4+1/4*5+1/5*6+1/6*7+……+1/99*100=1/2-1/3+1/3-1/4+1/4+1/5……+1/99-1/100=1/2-1/100=49/100

可以分解为：
1/（3*4）+1/（4*5）+……+1/（99*100）

1/6+1/12+1/20+1/30+1/42 1/3-1/12-1/20-1/30-1/42 1／6+1／12+1／20+1／30+1／42 1/12+1/20+1/30+1/42+.+1/2450 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72 1/2+1/6+1/12+1/20+1/30+1/42+1/56 简算 1/2+1/6+1/12+1/20+1/30+1/42+1/56简算, 1/12+1/20+1/30+1/42+1/56+1/72+1/90 简便运算：1/2+1/6+1/12+1/20+1/30+1/42+1/56 1+1/2+1/6+1/12+1/20+1/30+1/42的简便计算 2/1+6/1+12/1+20/1+30/1+42/1+56/1=? 1/12+1/20+1/30+1/42+1/56+1/72+1/90 1/6+1/12+1/20+1/30+1/42+1/56+1/72 简便计算 1/2 - 1/6 - 1/12 - 1/20 - 1/30 - 1/42 - 1/56怎么算 1+1/2+1/6+1/12+1/20+1/30+1/42=? 1/2+1/6+1/12+1/20+1/30+1/42+1/56 1/2-1/6-1/12-1/20-1/30-1/42-1/56等于多少