The number of digits in the square root of 625686734489 is 

What approximate values should come in place of the question mark(?) in the following question?

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

Simplification the following equations shown below

What approximate value should come at place of the question mark(?) in the following question?

Direction : What value should come in the place of question mark (?) in the following questions?

125% of 2440 – 75% of 1856 = ?

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