$958 \times 21 \div 4 = ?$

The last digit,that is,the digit in the unit's place of the number $[(57)^{25}-1]$ is

What is the remainder when $2468$ is divided by $37$?

$\sqrt{3 \sqrt{3 \sqrt{3 \sqrt{3 \sqrt{3 \sqrt{3}}}}}}=?$

Two-third of a positive number and $\frac{25}{216}$ of its reciprocal are equal. The number is

One-fifth of a number is equal to $\frac{5}{8}$ of another number. If $35$ is added to the first number,it becomes four times the second number. The second number is