$P, Q$ and $R$ scored $581$ runs such that $4$ times $P$'s runs are equal to $5$ times $Q$'s runs,which are equal to $7$ times $R$'s runs. Find the difference between $P$'s runs and $R$'s runs.

Two baskets together have $640$ oranges. If $\frac{1}{5}$ of the oranges in the first basket are taken to the second basket,the number of oranges in both baskets becomes equal. The number of oranges in the first basket is:

$\frac{16}{24} + \frac{4}{10} - \frac{1}{6} = ?$

If $2 \frac{1}{2}$ is added to a number and the sum is multiplied by $4 \frac{1}{2}$,and $3$ is added to the product,and then dividing the sum by $1 \frac{1}{5}$,the quotient becomes $25$. What is the number?

$\left[ {8\left\{ {\left( {\frac{{21 \times \sqrt {\frac{9}{{441}}} }}{5} \text{ of } 60\% - \frac{1}{5}} \right) \times 625 + 7} \right\} \div 4} \right] = ?$

$[(7.98)^{2} - (13.002)^{2} + (4.02)^{3}]^{2} = ?$