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

$\frac{753 \times 753 + 247 \times 247 - 753 \times 247}{753 \times 753 \times 753 + 247 \times 247 \times 247} = ?$

The quotient arising from a division of a number by $62$ is $463$ and the remainder is $60$. What is the number?

The numerator and denominator of a fraction are in the ratio of $2:3$. If $6$ is subtracted from the numerator,the result is a fraction that has a value $\frac{2}{3}$ of the original fraction. The numerator of the original fraction is

What least number should be subtracted from $3401$ so that the result is completely divisible by $11$?

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