The symbol for “average” in mathematics is an emphasised “x” with a horizontal line above it. Other sorts of averages exist, but the mean is the most prevalent.
The terms “mean” and “median” both refer to averages. The “mean” is calculated by adding a group of numbers and then dividing by the number of numbers in the original group. Because the sum of the three integers is 51, the average of 13, 15, and 23 equals 17. This number divided by three, the number of items in the group, equals seventeen. In contrast, the “median” is the number in the middle of a set of successive numbers. The median of the above list is 15.