Direction: What approximate value will come in place of the question mark (?) in the following question? (You are not expected to calculate the exact value)

(31.99)^1/5 × (80.78)^1/4 × (5.15)² = ? × 2.29

The value of x in the given equation
$$ {23 ^2 + \sqrt{x}=625}$$

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

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

If  $$\sqrt{2}=1.414$$, the value of $${ \sqrt{2}-1\over\sqrt{2}+1}$$  is nearest to 

The smallest number that must be subtracted from 1000 to make the resulting number a perfect square is 

Simplify the following expression.

 25-(4÷2)+11.5+9.5

On simplification of   $$ {(2.664)^2-(2.356)^2\over0.288}$$