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Maths
(media.piefed.world)
My dyscalculic ass trying to remember what 50% of 6 is
Probably 5 tbh
6/100 * 50 = 50/100 * 6
6 * 1/100 * 50 = 50 * 1/100 * 6
6/100 * 50 = 50/100 * 6
=6x5 /10 (2 zeroes cancel out)
6*50/100 = 50*6/100 if anyone is curious why this works.
Or, more generally:
Taking X percent of something is the same as multiplying by X/100.
X percent of Y = Y(X/100)=(YX)/100
Y percent of X = X(Y/100)=(XY)/100
(YX)/100=(XY)/100
Percentages are indeed reversible.
Most of the people explaining this still make it more complicated than it needs to be, imo.
I just think the symbol "%" algebraically means 0.01
I just think the symbol “%” algebraically means 0.01
Warm. It actually means "per 100", hence the slash to represent a vinculum and the 2 zeroes. Of course in decimal that converts to 0.01.
commutable...
This is the coolest trick since I learned about the "quick 20% tip on your tab" method. Take the total bill, move the decimal point one place over to the left, then multiply it by 2 to get 20% gratuity. I will sometimes round down on the change to make it closer to 18%. Also I only really need to do this when I'm drunk and can't maths.
Huh. Learning a fun and cool math trick was not on the list of expected outcomes for today, but I'll take it!
Today I learned, thank you wise panzer
Wise panzer of the lake. There are other wise panzers, but they are malevolent, untrustworthy.
Surprised how many people don’t know this. I suspect it is because people forget that percent literally means per 100 or /100 and the of is standing in for multiplication. So 6% of 50 is 6/100 * 50 or 6 * 50 * 1/100
people forget that percent literally means per 100 or /100
Yes
the of is standing in for multiplication
No. The M is for Multiplication. O is for Order, as in "to the order of", as in Exponents.
There is no 'M' or 'O' in the statement "six percent of fifty" There also is no exponentiation so I have no idea what you are on about
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Can we say "commutative" in this case ?
Yeah stuff like that really ain't it. It works in a few use cases, but is objectively wrong and detracts from understanding the topic properly. That's why I teach percentages as the fractions they are. By the time you learn percentages, you already know multiplying fractions is commutative, so the trick still works, and you also understand why.
Yeah stuff like that really ain’t it
Yes it is
It works in a few use cases,
It works in every case where you have multiplying and dividing, including fractions and percentages
but is objectively wrong
No it isn't
detracts from understanding the topic properly
Enhances it actually
That’s why I teach percentages as the fractions they are.
Sounds like you're only teaching as much as you understand. Try understanding more. Students love the tricks that make Maths easier, including this one.
that’s why I teach percentages as the fractions they are
What about pi%?
That's pi/100 still. Didn't say it was a rational number, just that it was a fraction. Though I don't see a context where it'd make sense.
Yeah, now calculate 6% of 36
Edit: Replies itt make me believe that everyone on Lemmy is a chatbot
Yeah, now calculate 6% of 36
6x3x10 + 6x6, move decimal point 2 places to the left
Replies itt make me believe that everyone on Lemmy is a chatbot
I'm a Maths teacher :-)
6x3x10 + 6x6, move decimal point 2 places to the left
Wow, that's nice! I like it.
I'm a Maths teacher :-)
I just hope that you are not starting grading your students with the phrase "You're absolutely right!"
Wow, that’s nice! I like it
It's called grouping. It's part of the curriculum here. Break the arithmetic into easily calculated groups.
I just hope that you are not starting grading your students with the phrase “You’re absolutely right!”
I'm not in the U.S. no. We still require teachers to be qualified here (Masters)! 😂
Bout tree fiddy
6% of 36 is 0.06 * 6². 6³ = 216 so 2.16
1% of 36 is .36, and .36 * 6 = 2.16. I'm a fan of this method most of the time, though the one in the OP is good for some math problems.
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For real? I've never though of this. This may actually be useful!
% really just means *1/100 - it doesn't matter where you apply that factor:
6% of 50 = 6% * 50 = 6/100 * 50 = 6*50/100 = 6 * 50/100
Where were you when I failed math 101 4 times?
Thanks!
I was probably on a different continent ^^ Also, the biggest problem explaining math is not making it understandable, but having a motivated learner. Most students that have a bad teacher in school, or are somehow not motivated in school to begin with, will also not be motivated to focus on easier explanations. Technically a basic interest in math should be fostered / encouraged in kids from an early age, and at the latest in elementary school. If that does not work out, many students will have a hard time with it.
You are welcome.
maths is the same in both case but I get it, for small numbers this is useful
For those who want to dive deeper into the lake and the wisdom of the panzer: https://en.m.wikipedia.org/wiki/Commutative_property
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this post was submitted on 02 Sep 2025
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