9999x36+6666x96
=9999*36+2*3333*3*32
=9999*36+9999*64
=9999*(36+64)
=9999*100
=999900
1-2-3+4+5-6-7+8+……+1997-1998-1999+2000
=(1-2-3+4)+(5-6-7+8)+……+(1997-1998-1999+2000)
=0+0+……+0
=0