$$\frac{{{{\left( {489 + 375} \right)}^2} - {{\left( {489 - 375} \right)}^2}}}{{\left( {489 \times 375} \right)}} = ?$$

Correct Answer: 4
Given expression :
$$ = \frac{{{{\left( {a + b} \right)}^2} - {{\left( {a - b} \right)}^2}}}{{ab}}$$     (where a = 489, b = 375)
$$\eqalign{ & = \frac{{4ab}}{{ab}} \cr & = 4 \cr} $$