First, figure out each distance:
1. -4 to 18 = 22
2. 18 to 7 = 11
3. 7 to -2 = 9
4. -2 to -6 = 4
5. -6 to 23 = 29
6. 23 to 2 = 21
7. 2 to 6 = 4
Now just add all the movement numbers up and then divide by the number of movements (7).
I hope this helps!