Math seems straightforward—until you realize how many common problems trip people up. Even simple equations can confuse the best of us, especially when tricky rules or hidden patterns are involved.
Think you’re good at math? Test yourself with these 10 problems that most people get wrong.
1. 6 ÷ 2(1+2) = ?
This one sparks debates online all the time. The correct answer is 9, but many people mistakenly get 1. The key is following the order of operations (PEMDAS)—solve parentheses first, then multiplication and division from left to right.
2. What’s 0.999… as a fraction?
Most people assume 0.999… is just shy of 1. But mathematically, it’s actually equal to 1! This can be proven by setting x = 0.999… and solving 10x – x = 9, which simplifies to x = 1.
3. If a bat and ball cost $1.10 and the bat costs $1 more than the ball, how much is the ball?
Your brain might jump to 10 cents, but that’s wrong. The correct answer is 5 cents. If the ball is $0.05, the bat must be $1.05, which adds up to $1.10.
4. What’s 8 + 8 ÷ 8 + 8 × 8 – 8 = ?
Many get confused and end up with the wrong number. The correct answer is 57. Using PEMDAS, division and multiplication come first: 8 ÷ 8 = 1, 8 × 8 = 64. Then add and subtract: 8 + 1 + 64 – 8 = 57.
5. How many months have 28 days?
Most people say one (February), but the right answer is all 12 months—every month has at least 28 days!
6. A farmer has 15 sheep and all but 9 run away. How many are left?
It sounds like you should subtract, but read carefully—“all but 9” means 9 sheep remain. The answer is 9, not 6.
7. What’s ½ + ½ × ½?
If you add first, you might get 1. But following PEMDAS, you multiply first: ½ × ½ = ¼, then add ½, which equals ¾.
8. What’s the square root of 16?
Most say 4, but there are actually two correct answers: 4 and -4. Any number squared equals a positive value, so both work!
Read More: No One Can Agree When It Comes to These 20 Controversial Food Takes
9. If it takes 5 machines 5 minutes to make 5 widgets, how long would it take 100 machines to make 100 widgets?
The trick is in the pattern. If 5 machines make 5 widgets in 5 minutes, then 1 machine makes 1 widget in 5 minutes. So 100 machines still take 5 minutes to make 100 widgets.
Read More: Why Is Investing in the Stock Market so Confusing?
10. If you’re running a race and you pass the person in second place, what place are you in now?
Most people instinctively say first place, but that’s incorrect. If you pass the person in second place, you take their position. That means you’re now in second place, not first!
Read More: The 15 Worst In-Car Tech Advancements Ever
