2\1-6\1-12\1-20\1-30\1-42\1-56\1-72\1-90\1

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+.1/9900 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/10 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110 谁能巧算1-1/2-1/6-1/12-1/20-1/30-1/42-1/56-1/72-1/90 2/1+6/1+12/1+20/1+30/1+42/1+56/1+72/1+90/1等于多少 2\1-6\1-12\1-20\1-30\1-42\1-56\1-72\1-90\1 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90简便计算 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90简算 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 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=多少