Mode - the most frequently occurring numbers in a set of data.

  example:
                3,5,7,7,9 the mode is 7
                4,4,4,8,8,8,8,9,15 the mode is 8
                6,13,18,19,21, there is no mode
                24,24,24,38,38,38,47,47,47 there is no mode