计算:1/2+1/6+1/12+1/20+/+1/30+1/42+1/56+1/72+1/90
化学计算1(化学计算)
化学计算1(化学反应计算)
计算:1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90(要求简便计算)
计算:1-56
计算:(1+12
计算:(1−12
计算.(1-12
1:计算.2:填一填.
计算:1/6+1/12+1/20+1/30……+1/2009*2010 简便计算
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90简便计算
计算1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
计算:1/2+1/6+1/12+1/20+/+1/30+1/42+1/56+1/72+1/90