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   clacke (clacke@libranet.de)'s status on Sunday, 07-Apr-2024 21:39:29 JST clacke

   Every year for the last 13 years, some post makes the rounds complaining that calculators disagree on what an expression like 8/2(2+2) or 6÷2(1+2) means.

   And every time some loud people show up saying people are idiots if they don't know there's One Correct Answer, and if you know Math you know the Answer.

   Here's science educator "The How and Why of Mathematics" with full receipts from papers around 1917 and full receipts from maths and physics publishing guidelines of today explaining that it's Just Not That Clear.

   It seems the people who think it is unambiguous are mostly people who went to US primary school and highschool and learned the PEMDAS initialism in the 1990s or later.

   She even goes through various calculator brands and what their representatives have said! Basically only Sharp calculators are consistent within their product lines, others have moved back and forth over time.

   farside.link/invidious/watch?v…
   youtube.com/watch?v=4x-BcYCiKC…

   If you don't like videos, Berkeley professor George Bergman has written something similar back in 2013 or so:

   math.berkeley.edu/~gbergman/mi…
   The Problem with PEMDAS: Why Calculators Disagree

   • Haelwenn /элвэн/ :triskell: and Fish of Rage like this.
   • Embed this notice
     clacke (clacke@libranet.de)'s status on Sunday, 07-Apr-2024 21:39:28 JST clacke

     in reply to
     In brief: What people learned about PEMDAS in primary school and highschool is an oversimplification of how actual mathematicians and math users write math in scientific papers.
     Haelwenn /элвэн/ :triskell: likes this.
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     Haelwenn /элвэн/ :triskell: (lanodan@queer.hacktivis.me)'s status on Sunday, 07-Apr-2024 21:41:18 JST Haelwenn /элвэн/ :triskell:

     in reply to
     @clacke And even with that I often end up being like "Screw it, give me RPN" because I hate having to put a bunch of parenthesises.
     clacke likes this.
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     clacke (clacke@libranet.de)'s status on Sunday, 07-Apr-2024 21:42:04 JST clacke

     in reply to

     The contention is "math has only one truth, it's not subjective!", but we are talking about human conventions and notations here, not the abstract nature of the concept of mathematical relations.

     In the real world, outside a given classroom that teaches one way, professional mathematicians do not even agree of whether the natural numbers include the number zero not.

     Smart people who want to communicate ideas will say "non-negative integers" or "positive integers" to be clear, rather than going on the barricades for the supremacy of a given interpretation. And professional mathematicians just do not write x/yz in their paper. Except when they do.

     Haelwenn /элвэн/ :triskell:, LinuxWalt (@lnxw48a1) {3EB165E0-5BB1-45D2-9E7D-93B31821F864} and gidi like this.
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     Tim Ward ⭐🇪🇺🔶 #FBPE (timwardcam@c.im)'s status on Sunday, 07-Apr-2024 21:43:24 JST Tim Ward ⭐🇪🇺🔶 #FBPE

     in reply to

     @clacke In real life the answer is "you don't write calculations like that because they might confuse people".

     Similarly for coding standards. "Do not write code that depends in subtle ways on the priority and association rules of your particular language, because not everybody will know that particular niche flavour of rules. If in even the slightest doubt PUT THE FUCKING BRACKETS IN. And if you're not in doubt, put them in anyway."

     (And then turn off any utterly insane linting rules that whine about superfluous brackets. And if you aren't allowed to turn off those rules ... find another job.)

     Haelwenn /элвэн/ :triskell:, clacke and gidi like this.
   • Embed this notice
     clacke (clacke@libranet.de)'s status on Sunday, 07-Apr-2024 21:46:57 JST clacke

     in reply to

     • Haelwenn /элвэн/ :triskell:

     @lanodan I never had a pocket calculator that accepted algebraic expressions. 😃

     In highschool I had a non-graphing RPN HP and at uni I didn't have use for a calculator.

     Haelwenn /элвэн/ :triskell: likes this.
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     Haelwenn /элвэн/ :triskell: (lanodan@queer.hacktivis.me)'s status on Sunday, 07-Apr-2024 21:51:21 JST Haelwenn /элвэн/ :triskell:

     in reply to
     @clacke Nice, I quite wish I would have an RPN pocket calculator, although these days I tend to have a Unix on hand so I can reach for dc(1).
     
     Although I should probably adopt Forth at one point for some customisability via variables and functions.
     Fish of Rage likes this.
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     Fish of Rage (sun@shitposter.world)'s status on Sunday, 07-Apr-2024 21:52:08 JST Fish of Rage

     in reply to
     @clacke https://en.wikipedia.org/wiki/HP-35 Reverse Polish Notation ftw. Still have my dad's somewhere.
   • Embed this notice
     clacke (clacke@libranet.de)'s status on Sunday, 07-Apr-2024 21:58:11 JST clacke

     in reply to

     I've been surprised to see from US people and from kid's homework here in HK that people actually spell out the "÷" character.

     In Sweden we learned that "no no, nobody actually writes that symbol, that's just a button on the calculator that symbolises a number over another separated by a horizontal division bar".

     Haelwenn /элвэн/ :triskell: and gidi like this.
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     Haelwenn /элвэн/ :triskell: (lanodan@queer.hacktivis.me)'s status on Sunday, 07-Apr-2024 22:04:33 JST Haelwenn /элвэн/ :triskell:

     in reply to
     @clacke Interesting, made me look as I thought ÷ was the standard in France and slash being a programming thing but turns out both are accepted, I guess it's teachers I had preferring to reuse the calculator standard for less confusion.
     That said in second degree teachers tend to just write them as fractions, so slash it is.
   • Embed this notice
     clacke (clacke@libranet.de)'s status on Sunday, 07-Apr-2024 22:30:40 JST clacke

     in reply to

     • Fish of Rage

     @sun My highschool calculator was the HP 32S. Several years later I took it out of the drawer in my old room in my parents' home and it still ran. On the original batteries!

     en.wikipedia.org/wiki/HP-32S

     Fish of Rage likes this.
   • Embed this notice
     Fish of Rage (sun@shitposter.world)'s status on Sunday, 07-Apr-2024 22:31:04 JST Fish of Rage

     in reply to
     @clacke They don't make calculators like they used to :sip:
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     LinuxWalt (@lnxw48a1) {3EB165E0-5BB1-45D2-9E7D-93B31821F864} (lnxw48a1@nu.federati.net)'s status on Monday, 08-Apr-2024 00:46:32 JST LinuxWalt (@lnxw48a1) {3EB165E0-5BB1-45D2-9E7D-93B31821F864}

     in reply to
     @clacke Oh, yeah. We use it in the lower grades. And it is only later that they inform you why it looks that way, right around the time we switch to the front-slash.
     
     Also, I remember one instructor using the back-slash for truncated division (integer portion).
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     LinuxWalt (@lnxw48a1) {3EB165E0-5BB1-45D2-9E7D-93B31821F864} (lnxw48a1@nu.federati.net)'s status on Monday, 08-Apr-2024 00:51:50 JST LinuxWalt (@lnxw48a1) {3EB165E0-5BB1-45D2-9E7D-93B31821F864}

     in reply to
     @clacke I had a college instructor who said if there's any chance of misinterpretation you should be as clear and specific as possible. So write "x/(yz)" or "(x/y)z" as appropriate, even though "/" already has implied grouping.
   • Embed this notice
     clacke (clacke@libranet.de)'s status on Monday, 08-Apr-2024 00:58:55 JST clacke

     in reply to

     • Tim Ward ⭐🇪🇺🔶 #FBPE
     @TimWardCam yep yep yep