Every now and again, homework takes social media by storm. Sometimes it’s a young child’s vexing assignment, or a classic brain teaser.

But the problem above that’s stirred such debate is really just basic math. A video explaining the answer has racked up over 12 million views!

Can you transport yourself back to fourth-grade math class and come up with the solution?

Order of operations

To solve the equation, you need to brush up on the order of operations:

1. Parentheses
2. Exponents
3. Multiplication and Division (left to right)
4. Addition and Subtraction (left to right)

As the famous mnemonic goes, Please Excuse My Dear Aunt Sally.

In the problem above, that means we first need to tackle what’s inside the parentheses: (1+2) = 3.

Easy enough. So now we’re looking at 6÷2(3)=?

With no exponents to deal with, we move on to multiplication and division. 6÷2 is 3, and 3(3) is 9. There’s your answer.

As Presh Talwalker puts it over on Mind Your Decisions, “This is without argument the correct answer of how to evaluate this expression according to current usage.”

Why lots of people say the answer is 1

You might have forgotten that multiplication and division have the same priority in PEMDAS, and you go from left to right. Simple mistake.

But wait, what did Talwalker say about “current usage”? If you were solving this problem 100 years ago, you might have been taught that the ÷ symbol meant “you should divide by the entire product on the right of the symbol.”

So 6÷2(3) would be 6÷(2(3)). And 6÷6=1. Which is not correct unless you’ve managed to invent a time machine and use it to solve math problems during Woodrow Wilson’s presidency.

(This is not a great use of time travel technology.)

Here’s a more detailed explanation:

Watch this

Why You Need to Try Tai Chi