Use a simple method to calculate! (1)202²+198² 2)2005×20042004- 2004×20052005

Use a simple method to calculate! (1)202²+198² 2)2005×20042004- 2004×20052005

(1) (200+2)^2+(200-2)^2=2*200^2+2*2^2=80000+8=80008
(2) 2005*2004*10001-2004*2005*10001=0