Addition (+): 15 + 4 = 19
Subtraction (-): 15 - 4 = 11
Multiplication (*): 15 * 4 = 60
Division (/): 15 / 4 = 3.75
Modulus (%): 15 % 4 = 3
Exponentiation (**): 15 ** 4 = 50625
Pre-Increment (++): ++15 = 16
Post-Increment (++): 16++ = 16
Post-Increment (after): 17 = 17
Pre-Decrement (--): --4 = 3
Post-Decrement (--): 3-- = 3
Post-Decrement (after): 2 = 2
Negation (-): -15 = -15
Explanation: These operators perform mathematical operations. Modulus (%) returns the remainder, ** raises to a power, and ++/-- increment/decrement values by 1. Pre-increment/decrement changes the value *before* it's returned, while post-increment/decrement changes the value *after* it's returned.