6÷2(1+2) = ? Correct Answer Explained By Mathematician

What is 6÷2(1+2) = ? This problem went viral and generated millions of comments on Facebook, Twitter, YouTube and social media sites. I explain how to get the correct answer by using the modern interpretation of the order of operations. I also explain how you would get a different answer under historical usage of the division symbol. (Note: some people write 6/2(1 + 2) = but this has the same answer.)

I studied Mathematics and Economics at Stanford. Press coverage of my work:

*I get many, many emails about this problem and am unable to reply to them.

Slate explains the history of the division symbol

Here is a 1917 article from "The American Mathematical Monthly" that explains the usage of the division symbol as an exception to the order of operations

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[danielrushing]

1960 we will have flying cars in the future
2020: world debate over 5th grade math

[molo]

The correct answer is 9 but the way I was taught math makes me keep saying 1

[WhyThisMedia]

This is not a math problem... this is a rule problem....

[ronnycook]

IMO the real answer is "don't write expressions this way." You write expressions so that they can't be easily misinterpreted. If there's any possible confusion, add parentheses to resolve the confusion. This is particularly so when dealing with non-commutative operations such as subtraction and division.
This probably comes from a background in computer programming; you don't want to make assumptions about order of operations, because while the people who implement the languages usually have standards to work from, they sometimes screw up. (To make things even more complicated, in computer programs sometimes operations have side effects - like "x++ + x" in C - "x++" evaluates x then increments it, so the value depends on whether the left or right side of the addition is interpreted first. The solution is "don't write it that way.". Eliminates confusion and therefore bugs.)

[jamesgcrawford]

the correct answer is this is a poorly written problem.

[LeoHL]

We shouldn't change things like the order of operations, it's incredibly dangerous in things like engineering to have two different people unknowingly using two different standards.

[DJ_Dopamine]

I am 45 years old and have honours degrees in Engineering and Science.
We were always taught that the answer should be 1, because of the order of operations rule that we were taught to use.
If you change the rule, you change the answer.
I was not aware that the rules had changed!

[IILiamHD]

as an engineer who has done advanced university level maths for about 7 years now, I would get 1. its the convention usually followed in physics/engineering textbooks to solve as terms and let implicit multiplication (brackets esp) go first

[briannadeleon]

Just graduated and I was legitimately taught that "historical way" all through school

[erickbangle]

think of it like a fraction. there's a reason why in higher math '÷' isn't used.

[Shadex]

The programmer's wife sends him to the store. She says "Get one carton of milk, and if they have eggs, get a dozen". The programmer came home with 12 cartons of milk, because they did have eggs.

[ricflair]

If you substitute all numbers with variables:
a÷b(c+d) =
You would get a/b(c+d) =
a/(bc+bd)
Not a/b × (c+d)
That's how algebraic functions are ordered.

[mattmanhero]

The problem isint the equation itself, it's whoever wrote it.

[indy]

Its gonna go viral again because its in my recommended

[anvesha]

Next viral problem..
1+1 = 2 or 11.. 🤔🤔🤔

[netherworldofmind]

I can ensure you that in most Stem environments the symbols ÷ and / are pretty much forbidden, every division must be written as a fraction, so all formulas and expressions are just sequences of products of franctions, and the length of an horizontal line is clearer than any pemdas rule

[Pepapig]

As a math student, I’m mad at the way this is written. My teacher said he would fail anyone who wrote math problems like this 😂😂😂

[abvolts-animation]

I did this in 10 seconds... how can it be viral?

[ammarmar]

That's why nobody uses the division symbol. It's confusing and it leads to errors. Both in math and physics, fractions are the way to go.

[Deez]

I graduated in 2003. I was and am pretty good in math subjects. I was taught to solve this with the answer of 1. The brackets are to be dealt with b4 other division of multiplication occurs