2002*2002*(1/2000*2001+1/2001*2002)
=(2002*2002)/(2000*2001)+(2002*2002)/(2001*2002)
=(2002*2002)/(2000*2001)+(2002/2001)
=(2002/2000)(2002/2001)+(2002/2001)
=(2002/2000+1)*(2002/2001)
=(1001/1000+1)*(2002/2001)
=(2001/1000)*(2002/2001)
=2002/1000
=2.002
2002*2002*(1/2000*2001 + 1/2001*2002)=2002*2002*(1/2000 - 1/2001 + 1/2001 - 1/2002)
=2002*2002*(1/2000 - 1/2002)
=2002*2002*2/2000*2002
=1001/500