数学题怎么做？大家来看看！数学高手进！

1/2*1/3+1/3*1/4+1/4*1/5+……1/2001*1/2002
=(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+......+(1/2001-1/2002)
=1/2-1/3+1/3-1/4+1/4-1/5+......+1/2001-1/2002
=1/2-1/2002
=500/1001

以后遇到这类题一律拆开作差就可以了，中间数全消掉，剩1/2-1/2005=2003/4010

/2*1/3+1/3*1/4+1/4*1/5+……1/2001*1/2002
= 1/2-1/3+1/3-1/4+1/4-1/5+……+1/2001-1/2002
= 1/2-1/2002
=1000/2002