Glitch in the matrix

Toes♀@ani.social to 196@lemmy.blahaj.zone – 419 points –
573

You are viewing a single comment

PEMDAS

Parenthesis, exponents, multiplication, division, addition, subtraction.

The rule is much older than me and they taught it in school. Nothing ambiguous about it, homie. The phone app is fucked up. Calculator nailed it.

Left to right. If you’re following ALL of the rules of PEMDAS then the answer is 16

Multiplication before division bro.

The division goes last.

Answer is 1.

The answer is 1, but the logic you've used to get there is a little off. Different groups actually follow different logic, but they usually arrive at the same end-point.

The American Mathematical Society goes:

  • Brackets
  • Indices
  • Multiplication indicated by juxtaposition
  • Regular multiplication and division
  • Addition and subtraction

While the American Physical Society does

  • Brackets
  • Indices
  • Multiplication
  • Division
  • Addition and subtraction

In both cases, addition and subtraction are equal in priority (this solves the problem brought up by a different comment where following primary school BIDMAS would mean 8-4+2=2). In one case (and this is the way I prefer to do it) they solve the problem by declaring that implicit multiplication is done before division, but explicit multiplication with the Γ— sign follows the same rules you would have learnt in primary school. The other says all multiplication is done before division, including explicit multiplication.

By that logic: 8-2+4=2

Of course, it could be kind of ambiguous, but typical convention gives multiplication/division the same priority, as it does addition/subtraction.

And in general, you need to go left to right when dealing with division and subtraction, if other operations have the same priority.

The comment from subignition explains that the phone's answer, 16, is what you get by strictly following PEMDAS: the rule is that multiplication and division have the same precedence, and you evaluate them from left-to-right.

The calculator uses a different convention where either multiplication has higher priority than division, or where "implicit" multiplication has higher priority (where there is no multiply sign between adjacent expressions).

But explicit multiplication is part of the parenthesis, so still comes before division or exponent

16, is what you get by strictly following PEMDAS

except 1 is what you get from strictly following PEMDAS. If you got 16 then you missed one of more rules.

the rule is that multiplication and division have the same precedence, and you evaluate them from left-to-right

Go back and read your link again. You'll find they're obeying The Distributive Law. i.e. solve all brackets first, from inner-most out.

β€œimplicit” multiplication

There's no such thing as implicit multiplication

i know about pemdas and also my brother in christ half the people in the comments are saying the phone app is right lmao

edit: my first answer was 16