(1\2+1\3+...+1\2006)(1+1\2+1\3+...+1\2005)-(1+1\2+1\3+...+1\2006)(1\2+1\3+...+1\2005)
`````
参考答案:原公式=(1/2+1/3+……+1/2006)+(1/2+1/3+……+1/2006)*(1/2+1/3+……+1/2005)-(1/2+1/3+……+1/2005)-(1/2+1/3+……+1/2006)*(1/2+1/3+……+1/2005)
=(1/2+1/3+……+1/2006)-(1/2+1/3+……+1/2005)
=1/2006