How to use set formulas?

[ssy]

I've just come across these set formulas in past posts. Can someone please explain the difference between these 2 formulas (if there is a difference) and how to use them? Is this all or are there more set formulas which would be helpful?


Total = Group1 + Group2 + Group3 - (sum of 2-group overlaps) - 2*(all three) + Neither

Total = A + B + C - 2*(all3) - (only two)

How do we calculate "All three", "Neither" and "Only two"?

Thank you!