I've come across some issues trying to write a custom formula field. I have created 7 list selection fields with values from 1 to 10.

The idea of the formula field is to get the average value of those 7 fields, for example:

Field 1: 4
Field 2: 7

Field 3: 5

And so on. I'm getting Wrong data error and syntax error everytime. I'd really appreciate some help with this one. Cheers.