Nothing like a viral mind boggling math problem to make you feel like you should have paid better attention in high school algebra.

The equation in question? 9 – 3 ÷ 1/3 + 1 = ? The deceptively simply math problem recently blew up in Japan, as people quickly found they were routinely getting the wrong answer. According to PopSugar, only 60 percent of 20-somethings solve it correctly, a study showed.

So what is the remaining 40 percent doing right? YouTube user MindYourDecisions shows you, bringing in mathematician Presh Talwalkar, the man behind the problem, to explain how it’s done.

The trick is to remember PEMDAS, the order of operations formula, which stands for parentheses, exponents, multiplication, division, addition, subtraction. As Talwalkar explains, this means first tackling 3 ÷ 1/3. Three divided by 1/3 is nine, and then carrying along with the equation from left to right you end up with the correct answer of drum role, please: 1!

Unfortunately, it’s been a while for many of us (or it hasn’t but we just didn’t pay that much attention in algebra) and most people who get it wrong actually fall down on entering the fraction into a calculator. Other people who get it wrong forget about PEMDAS, and simply do the equation from left to right. Common incorrect answers end up being 3, 7, or 9.

Of course, it’s just a silly math problem or is it? According to the video, the 60% rate of correct answers is down from 90% in the 1980s. What could this big drop in accuracy suggest? Is it possible that our dependence on easy internet research and calculators means we’re committing fewer algebra principles, like PEMDAS, to memory? It’s a fascinating question, and we’re going to go look up the quadratic equation real quick, just in case.