* Bạn tham khảo nha >v< *
$a, ( 0,125 × 10 - \dfrac{125}{10} ÷ 10 ) × 2001 × 2002 × 2003$
$= ( 1,25 - 12,5 ÷ 10 ) × 2001 × 2002 × 2003$
$= ( 1,25 - 1,25 ) × 2001 × 2002 × 2003$
$= 0 × 2001 × 2002 × 2003$
$= 0$
$b, 28 + 62 × a × ( a × 1 - a ÷ 1 ) + 28 × 8 + 28$
$= 28 × ( 1 + 8 + 1 ) + 62 × a × ( a - a )$
$= 28 × 10 + 62 × a × 0$
$= 280 + 0$
$= 280$