An average, or the mean, is the result obtained by adding several quantities together and then dividing this total by the number of quantities. The average in lotto, is the sum of all lotto numbers in a drawing, divided by the pick-size or total number of lottery numbers in the group. Example: for lotto drawing 5-12-20-21-30, the average of these 5 numbers is (5+12+20+21+30)/5 or 88/5 = 17.6