This short math puzzle catches people who rush through the equation from left to right:
10 + 20 – 10 × 0 = ?
The key is the order of operations. Multiplication must be completed before addition or subtraction. First calculate 10 × 0 = 0. The expression then becomes:
10 + 20 – 0
Now the remaining arithmetic is simple: 10 + 20 = 30, and subtracting zero changes nothing.
Answer: 30.
The zero is what makes the puzzle look more confusing than it really is. Many people see the subtraction sign first and begin calculating left to right, but multiplication takes priority.
Did you get 30 on your first try?
