3+13/6+37/12+81/20+151/30+253/42+393/56+577/72+811/90怎样简算?

3+13/6+37/12+81/20+151/30+253/42+393/56+577/72+811/90=3+2+1/6+3+1/12+4+1/20+5+1/30+6+1/42+7+1/56+8+1/72+9+1/90=3+2+3+4+5+6+7+8+9+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=3+(2+9)*8/2+1/2*3+1/3*4+1/4*5+1/...