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submitted 11 months ago by Toes@ani.social to c/196@lemmy.blahaj.zone
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[-] Coreidan@lemmy.world 11 points 11 months ago

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

[-] 50MYT@aussie.zone 2 points 11 months ago

Multiplication before division bro.

The division goes last.

Answer is 1.

[-] Zagorath@aussie.zone 8 points 11 months ago

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 × sign follows the same rules you would have learnt in primary school. The other says all multiplication is done before division, including explicit multiplication.

[-] SmartmanApps@programming.dev 1 points 8 months ago

follows the same rules you would have learnt in primary school

It's never that - that's how people are getting the wrong answer. In high school you get taught about The Distributive Law.

[-] NikkiNikkiNikki@kbin.social 7 points 11 months ago

Multiplication and division have the same priority, whichever one comes first LTR is the one that gets resolved first, so it's (8 / 2) * 4

[-] SmartmanApps@programming.dev 1 points 8 months ago

it’s (8 / 2) * 4

It's 8/2(2+2)=8/(4+4) or 8/2(2+2)=8/2(4)=8/(2x4)

[-] jlh@lemmy.jlh.name 5 points 11 months ago

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.

[-] SmartmanApps@programming.dev 1 points 8 months ago

Right answer but wrong reason. It's because distribution comes first

[-] SmartmanApps@programming.dev 1 points 8 months ago

If you’re following ALL of the rules of PEMDAS then the answer is

...1. If you got 16 then there's one or more rules that you didn't obey.

this post was submitted on 03 Dec 2023
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