There are four different types of averages mean, mode, range and median.
Mean - add all numbers up and divide by how many numbers there are
Mode - most common
Median- the middle
Range - largest number take the smallest.
Mean = 5.454545...
6+5+12+8+23+18+1+(-2)+(-4)+(-3)+(-4) = 60
60/11 = 5.454545...
Mode = -4
Median = 5
-4, -4, -3, -2, 1, 5, 6, 8, 12, 18, 23
Range = 23- (-4) = 27