The arithmetic mean is a fancy term for the average. The simplest formula for mean or average adds up the numbers you want to average and divided by the number of items.
To write a simple mathematical expression for arithmetic mean or average or mean is,

The sum of \(k\) different numbers divided by \(k\).
A batsman scored the following number of runs in six innings:
\(36, 35, 50, 46, 60, 55\)
Calculate the mean runs scored by him in an inning.
Total runs \(= 36 + 35 + 50 + 46 + 60 + 55 = 282\).
To find the mean, we do the sum of all the observations and divide it by the number of observations.
Therefore, in this case, mean \(=\) 2826 \(= 47\).
Thus, the mean runs scored in an inning is \(47\).