Mean - a measure of central tendency.

The sum of a set of values divided by the number of the values in the set.

Lets try and figure out the mean to this set of numbers..

6, 4, 8,

add up all the numbers and divide the result by how many numbers there are::

6 + 4 + 8 = 18

18 divided by 3 = 6 

so the mean is 6.