1/20+1/30+1/42+.+1/132=?

来源：学生作业帮助网编辑：作业帮时间：2024/05/20 04:29:50

1/20+1/30+1/42+.+1/132
=1/4-1/5+1/5-1/6+----+1/11-1/12
=1/4-1/12
=1/6

1/20+1/30+1/42+......+1/132
=1/4*5+1/5*6+1/6*7+....+1/11*12
=1/4-1/5+1/5-1/6+1/6-1/7+....+1/11-1/12
=1/4-1/12
=1/6

(1/4-1/5)+(1/5-1/6)+(1/6-1/7)+...+1/11-1/12=1/4-1/12=1/6

原式=（1/4-1/5）+（1/5-1/6）+（1/6-1/7）+……+（1/11-1/12）
=1/4-1/5+1/5-1/6+1/6-1/7+……+1/11-1/12
=1/4-1/12
=1/6

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 1/20+1/30+1/42+1/56简便计算, 1/20+1/30+1/42+……+1/132 1/20+1/30+1/42+.+1/132=? 1/20+1/30+1/42+1/56=1/20+1/30+1/42+1/56= 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