What will come in place of the question mark (?) in the given questions?
$$\frac{2}{3}-\frac{5}{7}$$ of $$\frac{21}{23}$$ of $$\frac{46}{51} = ?$$ of $$\frac{8}{85}$$
$$\frac{\sqrt{(180)}\times\sqrt{(18)}\times\sqrt{(5)}\times\sqrt{(3)}}{\sqrt{(96)}\times5}=?$$