$12.1212 + 17.0005 - 9.1102 = ?$

If $\frac{1}{\sqrt{a}} - \frac{1}{\sqrt{b}} = 0$,then the value of $\frac{1}{a} + \frac{1}{b}$ is

If $\left(x+\frac{1}{x}\right)^{2}=3$,then the value of $x^{206}+x^{200}+x^{90}+x^{84}+x^{18}+x^{12}+x^{6}+1$ is

$A$ boy was asked to multiply a given number by $\frac{8}{17}$. Instead,he divided it by $\frac{8}{17}$ and got the result $225$ more than what he should have got if he had multiplied the number by $\frac{8}{17}$. The given number was:

The value of $\left\{\left(\sqrt[n]{x^{2}}\right)^{n / 2}\right\}^{2}$ is

$3 \frac{3}{4} + 4 \frac{2}{5} - 3 \frac{1}{8} = ?$