999×778+333×66620.09×37-200.9×1.9+2009×0.82

999×778+333×666 = 999×778+333× 3 ×222 = 999×778+999 ×222
= 999×（778+222 ） =999 × 1000 = 999000
20.09×37-200.9×1.9+2009×0.82 = 20.09×37-20.09×10×1.9+20.09×100×0.82
= 20.09 × (37 -19 + 82) = 20.09 × 100 = 2009

999000
2009

999*（778+222）=999000
20.9*（37-10*1.9+100*0.82）=2090