tính nhanh

LTKH

$⇒$ Đáp án$:$ $1$

$⇒$ Giải thích$:$

$\frac{(2003\times1999–2003\times999)}{(2004\times999+1004)}$

$=$ $\frac{2003\times(1999–999)}{[(2003+1)\times999+1004]}$

$=$ $\frac{2003\times(1999–999)}{(2003×999+999+1004)}$

$=$ $\frac{2003\times(1999–999)}{(2003×999+2003)}$

$=$ $ \frac{2003\times(1999–999)}{[2003\times(999+1)]}$

$=$ $\frac{2003\times(1999–999)}{(2003 × 1000)}$ $=$ $1$