A simple math problem is going viral on Twitter, and nobody seems to agree on how to solve it. It's now causing arguments everywhere — including right here at the BuzzFeed offices. Let's break it down.
It all started when Twitter user @pjmdoll shared this (seemingly) easy math problem, and asked their followers to figure out the answer:
Lots of people think the answer is 1.
But just as many think the answer is 16.
And now, these two sides are engaged in an all-out war.
Things are getting pretty heated.
People on BOTH sides of the aisle are flexing their math backgrounds in order to prove their point.
And even CALCULATORS can't agree on the right answer here.
Okay. So. WHAT the heck is going on here? Well, you probably remember PEMDAS (or BEDMAS, or BODMAS, depending on where you grew up). PEMDAS gives us a clear order for solving equations: Parentheses, then Exponents, then Multiplication/Division, and then Addition/Subtraction. Stay with me!!!!
So, in this equation, everyone agrees that the first step is to solve the stuff inside the parentheses. 2+2 = 4. Easy!
It's the next step where everyone gets MAD. What would you do here?
Some believe you do the "2(4)" part first.
After all, the 4 is in PARENTHESES. That's the "P" in PEMDAS. If you do that first, you'll get a final answer of 1.
But others believe you should do the "8 ÷ 2" part first, since the parentheses around the "4" connote MULTIPLICATION. In PEMDAS, division and multiplication are at the same level. And therefore, you would just go from left to right...
...which gives you a final answer of 16.
So now you're probably wondering: Who's correct? And the answer, according to experts, is...both.
PEMDAS is just a language humans made up to interpret math equations — and like any language, there's always room for interpretation and ambiguity.
Popular Mechanics asked Rhett Alain, PhD, a physics professor at Southeastern Louisiana University, to explain how people could be getting different — and correct — answers to this. Here's what he said:
This is the math version of, "What color is this dress? Blue and black or gold and white?" ... Of course this isn't math. This is convention. We have conventions on how to write these things just like we have conventions on how to spell stuff. But still, there are different conventions. Some people spell it as "gray" and others as "grey." We still understand what's going on.
In other words, numbers are unchangeable, concrete things. But the ways that humans have decided to read and interpret numbers...sometimes leave room for a little opinion.
And Allain also pointed out that the equation could be written more clearly to avoid this confusion in the first place:
For me, I would write this more explicitly so that there is no confusion. Like this:
8/(2*(2+2)), if that's what you are trying to do. That way no one will get it wrong.