The least number that must be subtracted from $63520$ to make the result a perfect square is

Simplify:
$\frac{a^{1 / 2}+a^{-1 / 2}}{1-a}+\frac{1-a^{-1 / 2}}{1+\sqrt{a}}$

In a college,$\frac{1}{5}$ of the girls and $\frac{1}{8}$ of the boys took part in a social camp. What part of the total number of students in the college took part in the camp?

The value of $4-\frac{5}{1+\frac{1}{3+\frac{1}{2+\frac{1}{4}}}}$ is:

If $(\frac{5}{9} \text{ of } x) - (\frac{2}{5} \text{ of } \frac{9}{4}) = -\frac{4}{5}$,then find $x$.

$\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right)\left(1-\frac{1}{5}\right) \ldots \left(1-\frac{1}{25}\right)$ is equal to