Every few months a math problem goes viral on social media. The answer almost always comes down to order of operations.
Ask ten experts and you will get twelve answers. The underlying math, thankfully, only has one. Every few months a math problem goes viral on social media. The answer almost always comes down to order of operations.
Parentheses → Exponents → Multiplication/Division (L→R) → Addition/Subtraction (L→R).
6 ÷ 2(1+2) = ? Strict PEMDAS says 9. Many calculators say 1. Notation is ambiguous — write it clearly.
Implicit multiplication (juxtaposition) is treated as higher priority by many calculators. Use parentheses to remove all doubt.
Why do calculators disagree? Some give juxtaposition higher priority than ÷. Read your manual.
Does it matter in real math? In rigorous mathematics, you'd never write something ambiguous. It's a notation problem, not a math problem.
Run your own numbers before you trust a rule of thumb. Two minutes saves a lot of regret.