The number of digits in the decimal expansion of $16^5 \times 5^{16}$ is

$\frac{\sqrt{2}}{\sqrt{2 + \sqrt{3}} - \sqrt{2 - \sqrt{3}}} = $

$\sqrt {[10 - \sqrt {24} - \sqrt {40} + \sqrt {60}]} = $

Let $\frac{7}{2^{1/2} + 2^{1/4} + 1} = A + B \cdot 2^{1/4} + C \cdot 2^{1/2} + D \cdot 2^{3/4}$,where $A, B, C, D$ are rational numbers. Which of the following is true?

$({x^5})^{1/3} \times (16{x^3})^{2/3} \times \left( \frac{1}{4}{x^{4/9}} \right)^{-3/2} = ?$

The rationalizing factor of $2\sqrt{3} - \sqrt{7}$ is: