Directions (Set of 5 questions): What approximate value should come in place of the question marks(?) in the following questions? (Note : you are not expected to calculate the exact value.)
$321.12\times 22.81-~?~\times 121.89=~\sqrt{2118}$
Solution
$321.12\times 22.81-~?~\times 121.89=~\sqrt{2118}$
$?\times 121.89~\approx 321\times 23-46$
$?\times 122~\approx 7383-46$
$?=\frac{7337}{122}=60.13$
$?~\approx 60$