Find three rational numbers between $0.1$ and $0.11$.

Simplify the following expression: $(\sqrt{15}+\sqrt{7})(\sqrt{15}-\sqrt{7})$

Insert a rational number and an irrational number between the following: $\sqrt{2}$ and $\sqrt{3}$

$\sqrt[4]{\sqrt[3]{2^{2}}}$ equals

Find the values of $a$ and $b$ in each of the following:
$\frac{7+\sqrt{5}}{7-\sqrt{5}}-\frac{7-\sqrt{5}}{7+\sqrt{5}}=a+\frac{7}{11} \sqrt{5} b$

The decimal representation of a rational number cannot be: