The question some weeks ago was about average. It is important to disinguish between three things, all of them giving an idea of the distribution of data. Only one of them needs calculations:
The Mode is simply the most frequent occuring value in the set of data.
The Median is the middle value of the set. If there is an even number of data, it is the average of the two middle values.
The Mean is the sum of all the data values divided by the number of data values.