What is the value of $68 \%$ of two-fifths of $550\, ?$

$1599 \times 199 \div 49 - 1398 + 3877 = ?$

If the sum of a number and its square is $182$,what is the number?

The sum of five consecutive even numbers of set-$A$ is $220$. What is the sum of a different set of five consecutive numbers whose second lowest number is $37$ less than double the lowest number of set-$A$?

What is the largest two-digit prime number?

The ten's digit of a two-digit number is greater than the unit's digit by $7$. If we subtract $63$ from the number,the new number obtained is formed by interchanging the digits. Find the number.