This math puzzle is short, but it is built around one of the most common order-of-operations mistakes. The expression is 15 + 15 × 0 + 5.
Do the multiplication first. Since 15 × 0 = 0, the expression becomes 15 + 0 + 5.
Answer: 20.
It can be tempting to work from left to right, but multiplication has priority over addition. Another common mistake is to assume that the zero wipes out everything in the expression. It does not; it only affects the term being multiplied by zero.
Once that is clear, the final calculation is simply 15 + 5.
