this post was submitted on 09 Nov 2023
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The panzer has spoken (sh.itjust.works)
submitted 1 year ago by [email protected] to c/[email protected]
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[โ€“] [email protected] 4 points 1 year ago* (last edited 1 year ago) (1 children)

No, I think we all learned that multiplication is commutative in late elementary school, and obviously that's an important thing to know.

But I think the original post tried to make it out to be some magical mathematical trick, and I really don't understand that. Maybe I misunderstood the post.

Edit: wow, "commutative" is a really hard word to spell.

[โ€“] [email protected] 4 points 1 year ago (1 children)

Yeah I think this is more about how you interpreted it, because it doesn't look like others took it as being an absolute magic trick rule and neither did I.

The Panzer of the Lake didn't use the word "commutativity" (fuck that really is hard to spell), but it gave out some wisdom that applied that rule by saying that "percentages are reversible": if the reverse of a percentage would be easier to calculate, you can use it and get the same answer. If it's not easier, well, then you're screwed ๐Ÿ˜ Oooooor depending on the situation you can use the a ร— b% = a ร— b / 100 commutativity trick:

7 ร— 8% = 0.56

7 ร— 8 / 100 = 0.56

[โ€“] [email protected] 4 points 1 year ago (1 children)

Oh, that is actually much more helpful. So, if you know your times tables, you can do percentages. You just have to use communitavatization.

Jokes aside, I really appreciate it. That made it much more easier to understand. Thank you.

[โ€“] [email protected] 2 points 1 year ago (1 children)

You're welcome! Glad I could give you an a-ha moment.

Having an intuitive feel for tricks like using the definition of operators or symbols to make your life (well, calculations at least) easier usually means that you either have to just be "naturally" talented at math which is really rare, or you've just had to grind grind grind math at eg. university, work or whatever. So unless someone was taught that above trick and they actually remember it from school, they might never come to think that "hmm % just means / 100 so that can make this easier to figure out in my head".