Simplify the following:

$4 \sqrt{28} \div 3 \sqrt{7}$

Simplify the following:

$4 \sqrt{12} \times 7 \sqrt{6}$

State whether the following statements are true or false

Every whole number is an integer.

Classify the following numbers as rational or irrational with justification:

$(i)$ $\sqrt{\frac{9}{27}}$

$(ii)$ $\frac{\sqrt{28}}{\sqrt{343}}$

Rationalise the denominator of the following:

$\frac{2}{3 \sqrt{3}}$

Value of $\sqrt[4]{(81)^{-2}}$ is