Simplify : $$ {(2x)^{2}-(2y)^{2}-(4x)^{2}}$$

The Value of $$ {\sqrt{6-\sqrt{17-2\sqrt{72}}}}$$ is closest to:

Find the value of given equations

$$\left({216\over1} \right) ^{-{2\over3}}÷\left({27\over1} \right) ^{-{4\over3}}=? $$

Simplify the following equation.
$$ {(100)}^{1\over2}.{(0.001)}^{1\over3}-{(0.0016)}^{1\over4}.{3}^{0}+({5\over4})^{-1} $$

The largest number of five digits, which is a perfect square is 

The least number, by which 1944 must be multiplied so as to make the result a perfect cube is 

The value of $$ {\sqrt{0.6912}+{\sqrt{0.5292}}\over {\sqrt{0.6912}-{\sqrt{0.5292}}}}$$ is:

Simplify the following expression.

 25-(4÷2)+11.5+9.5