The value of   $${(75.8)^2-(55.8)^2\over20}$$

The value of $${\sqrt{40+\sqrt{9\sqrt{81}}} }$$ is

What approximate value should come in place of the question mark (?) in the following question? 
21.9714 × (8.8749 - 4.9393) = ?

Direction : What should come in place of the question (?) in the following question.

140% of 450 + 24% of 650 =?

The number, whose square is equal to the difference between the squares of 975 and 585, is: 

(5.5)³-(4.5)³ is equal to : 

Evaluate: $${-(4-6)^2-3(-2)+।-6।\over 18-9÷3×5}$$