(1)999^2
999^2=(1000-1)^2=1000^2-2x1000x1+1=1000000-2000+1=998001
(2).0.5^100x4^101
0.5^100x4^101=0.5^100x4^100x4=(0.5x4)^100x4=2^100x2^2=2^102
(1)999^2
999^2=(1000-1)^2=1000^2-2x1000x1+1=1000000-2000+1=998001
(2).0.5^100x4^101
0.5^100x4^101=0.5^100x4^100x4=(0.5x4)^100x4=2^100x2^2=2^102