$425 \div 16.95 \times ? = 225$

$12.1212 + 17.0005 - 9.1102 = ?$

When $\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{5}-\frac{1}{6}\right)$ is divided by $\left(\frac{2}{5}-\frac{5}{9}+\frac{3}{5}-\frac{7}{18}\right),$ the result is:

If $1^{3}+2^{3}+\cdots+9^{3}=2025,$ then the value of $(0.11)^{3}+(0.22)^{3}+\cdots+(0.99)^{3}$ is close to

$(2 + \frac{3}{x}) \times (y + \frac{1}{2}) = \frac{31}{4}$,find the values of $x$ and $y$ if $x$ and $y$ are positive integers.

Twenty-one times a positive number is less than its square by $100$. The value of the positive number is: