Parentheses override precedence rules. int x = (2 + 3) * 4; forces addition first, yielding 20 instead of 14. Without parentheses, multiplication runs before addition. You can nest parentheses for complex expressions.
int y = ((5 + 3) * 2) - 1; evaluates innermost first: 5 + 3 = 8, then 8 * 2 = 16, then 16 - 1 = 15. Use parentheses for clarity even when not required. int avg = (a + b) / 2; is clearer than a + b / 2, which divides only b by 2 then adds a.