1+(-2)+3+(-4)+…+2001+(-2002);
=(-1)+(-1)+(-1)+(-1)……+(-1)
把每两个合成一个-1,共2002/2个=1001个-1
=1001*(-1)
=-1001
(-1/2)+(-5又1/5)-1-4.5+2又1/3+3又1/5
=-1/2-26/5-1-9/2+7/3+16/5
=(-1/2-9/2)+(16/5-26/5)-1+7/3
=-5-2-1+7/3
=-24/3+7/3
=-17/3
1+(-2)+3+(-4)+…+2001+(-2002);
=(-1)+(-1)+(-1)+(-1)……+(-1)
把每两个合成一个-1,共2002/2个=1001个-1
=1001*(-1)
=-1001
(-1/2)+(-5又1/5)-1-4.5+2又1/3+3又1/5
=-1/2-26/5-1-9/2+7/3+16/5
=(-1/2-9/2)+(16/5-26/5)-1+7/3
=-5-2-1+7/3
=-24/3+7/3
=-17/3