-1 OR 5*5=25

It depends on the context (logic vs programming language).

Common interpretations:

• Pure boolean logic: -1 is treated as True; 5*5=25 is True. True OR True = True.
• Bitwise in C-like languages (assuming (5*5==25) is 1): -1 | 1 = -1 (since -1 has all bits 1).
• Python-style boolean operator "or": -1 or (5*5==25) yields -1 (because -1 is truthy, so the left side is returned).

If you tell me the language or the exact meaning (is "=" equality or assignment? is this a bitwise OR or a logical OR?), I can give a precise result.