原式=
1+2+3+..+9-(1/2+2/2+..+8/2)+(1/3+2/3+..+7/3)-(1/4+2/4+..+6/4)+(1/5+2/5+..+5/5)-(1/6+2/6+..+4/6)+(1/7+2/7+3/7)-(1/8+2/8)+1/9
=45-36/2+28/3-21/4+15/5-10/6+6/7-3/8+1/9
=45-18+84/9-42/4+3-15/9+6/7-3/8+1/9
=30+(84-15+1)/9-(42+3)/8+6/7
=30+70/9-45/8+6/7
=30+(70*7*8-45*9*7+6*9*8)/504
=30+293/56
=35又13/56
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