1/6+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+1/90
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110=?
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90简便运算怎么做
简算:1+12/6+36/12+80/20+150/30+252/42+392/56+576/72
42/1+56/1+72/1+90/1+110/1
巧算:1/2+1/6+1/12+1/20+1/30+1/42+1/56=?
1+1∕6+1∕12+1∕20+1∕30+1∕42+1∕56+1∕72
1/2+1/6+1/12+1/30+1/42
1又1/6+2又1/12+3又1/20+4又1/30+5又1/42+6又1/56+7又1/72 急
能简算的要简算 1/30+1/42+1/56+1/72
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20 =
递等式计算:1/42+1/56+1/72+1/90+1/110