2/1+6/1+12/1+20/1+30/1+42/1

来源：学生作业帮助网编辑：六六作业网时间：2024/12/29 08:47:39

2/1+6/1+12/1+20/1+30/1+42/12/1+6/1+12/1+20/1+30/1+42/12/1+6/1+12/1+20/1+30/1+42/1=1×2/1+2×3/1+3×4/1+

2/1+6/1+12/1+20/1+30/1+42/1
2/1+6/1+12/1+20/1+30/1+42/1

2/1+6/1+12/1+20/1+30/1+42/1
=1×2/1+2×3/1+3×4/1+4×5/1+5×6/1+6×7/1
=1/1-2/1+2/1-3/1+3/1-4/1+4/1-5/1+5/1-6/1+6/1-7/1
=1-7/1
=7/6

2%1+6%1+12%1+20%1+30%1 1/2+1/6+1/12+1/20+1/30 1/2,-1/6,1/12,-1/20,1/30 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+1/2+1/12+1/6+1/20+1/30+1/40+1/56 1+1/2+1/6+1/12+1/20+1/30.+1/901+1/2+1/6+1/12+1/20+1/30+.+1/90简便计算 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, 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=? 1/2 - 1/6 - 1/12 - 1/20 - 1/30 - 1/42 - 1/56怎么算 1/2+1/6+1/12+1/20+1/30+.1/380+1/420= 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 2/1+6/1+12/1+20/1+30/1+42/1+56/1=