Multiple choice What is the value of the expression '1 2 3 + * 3 2 1 - + *'? 0 20 10 None of these Reveal answer Fill a bubble to check yourself B Correct answer Explanation The expression '1 2 3 + * 3 2 1 - + *' is in postfix notation. Evaluating it: (1 * (2 + 3)) * (3 + (2 - 1)) = 5 * 4 = 20.