\(F1 = \frac{\frac{\sum{f_{i}}}{N} - \frac{\sum{c_{i}}}{N}+ 100}{2}\)

\(F2 = \frac{\sum{f_{i}}}{2N} - \frac{\sum{c_{i}}}{2N}+ 50\)

\(F3 = \frac{\sum{f_{i}} - \sum{c_{i}}}{2N}+ 50\)

\(F4 = \frac{\sum\limits_{i=1}^{n}{f_{i}} - \sum \limits_{i=1}^{n}{c_{i}}}{2N}+ 50\)

\(F5 = \frac{1}{2N}\sum\limits_{i=1}^{n}{f_{i}} - \frac{1}{2N}\sum \limits_{i=1}^{n}{c_{i}}+ 50\)

I've labeled them F1 through F5 to distinguish them.

Thank you in advance.