What least value should be added to $2505$ so that it becomes a perfect square?

The simplification of $\frac{0.8 \times 0.8 \times 0.8 - 0.5 \times 0.5 \times 0.5}{0.8 \times 0.8 + 0.8 \times 0.5 + 0.5 \times 0.5}$ gives:

The denominator of a fraction is $3$ more than the numerator. If the numerator as well as the denominator is increased by $4,$ the fraction becomes $\frac{4}{5}$. What was the original fraction?

What is the value of $\frac{(0.5)^{3}-(0.1)^{3}}{(0.5)^{2}+0.5 \times 0.1+(0.1)^{2}}?$

If $x - (1/x) = \sqrt{13}$,then what is the value of $x^5 - (1/x^5)$?

If $x = y = 333$ and $z = 334$,then the value of $x^{3} + y^{3} + z^{3} - 3xyz$ is