This is math.php
a = 10
b = 20
c = 30
Addition (a + b): 30
Subtraction (a - b): -10
Multiplication (a * b): 200
Division (a / b): 0.5
Modulus (a % b): 10
Pre-increment (++c + a): 41 , the final value is 41 since c was incremented before calculate c + a.
Post-increment (c++ + a): 40 , value c will increase after the calculation so the final value remains 30 + 10 which equals 40.
Pre-decrement (--c + a): 39 , the final value is 39 since c was decremented before calculate c + a.
Post-decrement (c-- + a): 40 , value c will decrease after the calculation so the final value remains 30 + 10 which equals 40.