0.25^2006×4^2005 —8^100×0.5^300=0.25*0.25^2005×4^2005 —8^100×0.5^100*0.5^100*0.5^100=0.25*(0.25*4)^2005-(8*0.5*0.5*0.5)^100=0.25*1^2005-1^100=0.25*1-1=-0.75