200705-2008x2006
=200705—(2007+1)x(2007-1)
=200705-2007×2007+1
=2007×100-2007×2007+6
=2007×(107-2007)-2007×7+6
=-2007×1900-2007×7+6
=-3827349+6
=-3827343
200705-2008x2006
=200705—(2007+1)x(2007-1)
=200705-2007×2007+1
=2007×100-2007×2007+6
=2007×(107-2007)-2007×7+6
=-2007×1900-2007×7+6
=-3827349+6
=-3827343