What value will come in place of the question mark (?) in the following question? (You are not expected to calculate the exact value)
$22.9889 \div ? = 23$

The value of $25 - 5[2 + 3\{2 - 2(5 - 3) + 5\} - 10] \div 4$ is

Find the smallest fraction which when added to $\frac{2}{5} \times \frac{15}{21} \times \frac{7}{10} \times \frac{3}{8}$ gives a whole number.

$A$ boy was asked to multiply a given number by $\frac{8}{17}$. Instead,he divided it by $\frac{8}{17}$ and got the result $225$ more than what he should have got if he had multiplied the number by $\frac{8}{17}$. The given number was:

Which of the following are in descending order of their value?

$3 \div \left[ (8 - 5) \div \left\{ (4 - 2) \div \left( 2 + \frac{8}{13} \right) \right\} \right] = ?$