One way is to make 5 the 3rd number in a series of equally spaced numbers:
3,4,5,6,7 = mean of 5
1, 3, 5, 7, 9 = mean of five
4, 4.5, 5, 5.5, 6 = mean of five
4.8, 4.9, 5.0, 5.1, 5.2 = mean of five
Do you get the idea?
If their mean is 5, then the numbers add up to 25.
Here are a few sets that do the job:
1, 2, 3, 4, 15
10, 20, 30, 40, -75
+2, -2, +99, -99, 25
1, 5, 5, 5, 9
