$617 + 6.017 + 0.617 + 6.0017 = ?$

$1 \frac{4}{7} + 1 \frac{3}{5} + 1 \frac{1}{3} = ?$

$4 \frac{1}{2} \times 4 \frac{1}{3} - 8 \frac{1}{3} + 5 \frac{2}{3} = ?$

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

If $\left(\frac{x}{y}\right)^{5a-3} = \left(\frac{y}{x}\right)^{17-3a}$,what is the value of $a$?

When simplified,the product $\left(2-\frac{1}{3}\right)\left(2-\frac{3}{5}\right)\left(2-\frac{5}{7}\right) \ldots \left(2-\frac{999}{1001}\right)$ is equal to