The HCF of $42, 63$ and $140$ is _____.

What value will come in place of the question mark (?) in the following question?

$12\%$ of $980-?\%$ of $450=30\%$ of $227$

Find the value of: 

$999\frac{995}{999}\times 999=?$

Find the value of:

$\frac{\sqrt{7} + \sqrt{5}}{\sqrt{7} - \sqrt{5}} = ?$