Today, I want to talk about those ambiguous viral PEMDAS problems that circulate on the Internet, with different people giving different answers. As an example, consider . I believe the reason it is ambiguous is because, technically, that expression is not a valid string of the PEMDAS language. This is a valid string of the PEMDAS language: . See, there is an extra multiplication symbol there. And the answer to that one is . If we are to allow juxtaposition, we need to expand the language, and also give new rules for evaluating multiplication by juxtaposition. That will make things even more complicated. Let us not make life more complicated than it has to be, life is complicated enough as it is. Anyway, that is just my judgement of those viral PEMDAS problems.
Comments
Following PEMDAS, the answer should be , not (the “M” comes before the “D”). In any case, I don’t like those “viral problems” because they reinforce the wrong impression many people have of maths as the following of arbitrary rules that you must know by heart!
Actually, the way I was taught is that multiplication and division have equal priority, and you work from left to right. Similarly, addition and subtraction also have equal priority, and you work from left to right.