What is the formula of average?

The average is given by the mean value which is equal to the ratio of the sum of the number of a given data set to the total number of values present in the data set.

This can be also given by the formula: $\mathrm{Average}= \frac{\mathrm{Sum} \mathrm{of} \mathrm{the} \mathrm{given} \mathrm{values}}{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{Values}}$.