The internet is no stranger to debates over puzzling questions, from the infamous “blue and black dress” to a viral math problem that sparked heated discussions across social media and workplaces alike. The problem in question—8 ÷ 2(2 + 2)—was shared on Twitter in 2019, igniting a controversy that drew in casual users, mathematicians, and even magazine editors.

The Divide Over PEMDAS
The editors of Popular Mechanics were among those split over the equation. Using the PEMDAS rule (Parentheses, Exponents, Multiplication, Division, Addition, Subtraction), one group explained their solution step by step:

Solve inside the parentheses first: 2 + 2 = 4.
The equation becomes 8 ÷ 2 × 4.
Apply division and multiplication from left to right: 8 ÷ 2 = 4, then 4 × 4 = 16.
This group argued that following PEMDAS strictly means handling operations in the order they appear, moving left to right for division and multiplication.

However, another faction interpreted PEMDAS differently. They believed the multiplication implied by the parentheses—2(4)—took precedence over division. Their reasoning led them to treat the equation as 8 ÷ [2(4)], effectively solving it as 8 ÷ 8 = 1.

Experts Weigh In
As the debate spread, mathematicians and scientists offered their perspectives. Mike Breen, from the American Mathematical Society, stated that by conventional rules, 16 is the correct answer. Yet, he acknowledged the ambiguity in how the equation is written.

“In math, a lot of times, there are ambiguities,” Breen said. “Mathematicians try to make rules as precise as possible. According to the strict order of operations, you’d get 16, but I wouldn’t fault someone for saying 1.”

Physics professor Rhett Allain from Southeastern Louisiana University added his take, explaining that the issue lies in differing conventions. To remove ambiguity, he suggested rewriting the problem as 8 ÷ (2 × (2 + 2)), which yields the answer 1.

A Matter of Interpretation
At its core, the controversy highlights the nuances of mathematical conventions and how they can vary. As Allain put it, “This is convention. We have conventions on how to write these things, just like we have conventions on how to spell stuff. Some spell it ‘gray,’ others ‘grey,’ but we still understand the meaning.”

While the debate may never reach a universal consensus, the viral math problem has shown how even a simple equation can spark complex discussions.