\(2004^2-4^2=2004^2-4.2004+4.2004-4^2\)
\(=2004\left(2004-4\right)+4\left(2004-4\right)=\left(2004+4\right)\left(2004-4\right)=2008.2000=4016000\)
2004² - 16
= 2004² - 4²
= (2004 - 4)(2004 + 4)
= 2000.2008
= 2000.2000 + 2000.8
= 4000000 + 16000
= 4016000