Find the missing digit in the expression: $60 ? 6 \times 111 = 666666$.

$4 \frac{4}{5} \div 6 \frac{2}{5} = ?$

The sum of three numbers is $264$. If the first number is twice the second and the third number is one-third of the first,then the second number is:

$P, Q$ 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.

Which number should replace both the $*$s in $\left(\frac{*}{21}\right) \times \left(\frac{*}{189}\right) = 1$?

The sum of the digits of a two-digit number is $8$. If the digits are reversed,the number is increased by $54$. Find the number.