$46818 + 34484 - 24642 - 21232 = ?$

$2 \times 256 \times ? = 8^{2} \times 10^{2} \times 2$

The value of $x$ in the following equation is
$0.3+0.6+0.7+0.8=x$

The product of two natural numbers is $17$. Then the sum of the reciprocals of their squares is

Find the number nearest to $16386$ which is exactly divisible by $425$.

The numerator of a fraction is the product of two numbers. One of the numbers is greater than the other by $2$. The greater number is smaller than the denominator $D = 7+c$ (where $c > -7$ is a constant). If the fraction is $f(x) = \frac{(x-2)x}{x+k}$ (where $x$ is the greater number),find the minimum value of the fraction.