magic square with symbols

[mayorchomo]

Hi I have a tricky magic square to solve with symbols in the square and I can't figure the answer.
If anyone could help me find an answer and explain how they got it I would appreciate it.

The goal is to find what number goes in the blank square bottom right.

Sorry if this is in the wrong section, I wasn't sure where to put it.

 

[stapel]

If anyone could help me find an answer and explain how they got it I would appreciate it.

The goal is to find what number goes in the blank square bottom right.

"The" answer will depend upon what the rules are (that is, what is being asked of you). So: what are the rules? What information, other than the square itself, have you been given?

When you reply, please include a clear listing of your thoughts and efforts so far, so we can see where you're getting stuck. Thank you!