My dyscalculic ass trying to remember what 50% of 6 is
is tree fiddy
Probably 5 tbh
commutable…
For those who want to dive deeper into the lake and the wisdom of the panzer: https://en.m.wikipedia.org/wiki/Commutative_property
I’m gonna track down all my HS math teachers and punch each and every one of them in the mouth.
I’m gonna track down all my HS math teachers and punch each and every one of them in the mouth.
Understandable if you’re in the U.S., where Maths teachers don’t have to have any Maths qualifications. Other places, where you do have to have Maths qualifications, we teach this.
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Danke
This is great. I won’t remember it when I will need it.
Just save the meme in the maths folder!
You clearly don’t have gigs of memes.
(Maths folder is clearly for porn)
(The maths IS the porn)
Ohhh … ‘Seven ate nine’, now I get it.
(As sexy math, not a ST reference.)Meh, either way 😂
Surprisingly not as useful as u would think unfortunately
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.
that’s why I teach percentages as the fractions they are
What about pi%?
Yes, 47% of 47 is certainly much easier to determine when you look at it as 47% of 47! Genius!
You can also
Multiply one side, divide the other to get the base number to get the base number to 100.
6% of 50 == 3% of 100 == 3
5% of 20 == 1% of 100 == 1
7% of 50 == 3.5℅ of 100 == 3.5
14% of 200 == 7% of 100 == 7
You don’t have to stop at percentage either.
25 * 16 = 100 * 4
If you’re doing addition, you can add and subtract.
27 + 13 = 20 + 20
Most of the difficulty is in realizing that one number or the other can be brought up to a nice round number, making the equation simple to do in your head. And obviously, just getting to around number on one side doesn’t always make it easy on the other side.
I always loved screwing with math problems to make them easier, which is weird, because overall, I don’t really care for math.
I also do shit like borrowing a couple of numbers to make the equation easy and then pull them back out.
392 / 4 == (400 - 8) / 4 == (100-2) = 98
376 / 4 == (400-24)/4 =100-6=94
Of course it goes up a level when the remainder isn’t evenly divisible. But I still find it’s something I can handle in my head.
371 / 4 == (400-29)/4= 100-7¼ =100-7.25=92.75
Are you just out here doing common core math on here like it’s just some smart trick to make math easier?! You dirty bastard, some conservative is going to see this and think it’s a good idea, then they’ll just innocently do it in front of their conservative friends and all hell will break loose. Homosexual fornication will suddenly run rampant through the group and those few that can resist the call of the devils numbers will have to cull the rest. You know… Actually… I am not completely against that now that I think about it…
Rofl, I pre-date common core. I’m not exactly sure to what extent they do all that stuff. I do know that they’ve got a fuck of a lot of numberlines, like so many number lines. Like they’re being paid by the number line.
Back in the 80s and 90s, the teachers would do regular scrolling down arithmetic, and they would mention borrowing numbers and shortcuts. And I took that shit seriously because I did not like sitting down and adding/multiplying numbers. I’d probably spend an extra 30 seconds of problem if I thought I could not have to sit down and write equations.
That’s really cool. The borrowing thing is the part of common core that they teach in elementary, and it is the part that enrages conservatives. The point of the homework and practice questions is to repeatedly do the borrowing thing until it becomes automatic and something that they do in their heads all of the time. So, it absolutely enrages the right when kids get the correct answer, but lose points for doing the problem the wrong way.
I was taught to do it the hard way and had to figure out the other tricks for myself much later in life, so now, even after decades of doing it your way, it’s more of a struggle than it should be and I just reach for my calculator instead. So I envy you quite a bit.Keep up the good work with your subversive teaching of common core principles as tips, tricks, cheats and shortcuts. That’s actually how they should have branded it, instead of common core, it should have been cheating core, then they would have been all for it.
There’s nothing wrong with calculators.
I wonder if the next generation is going to be reaching for AI for all their English needs.
I haven’t sent anything to anyone that wasn’t spell checked in more than a decade. So, ya it’s going to be a weird future where you just choose the comment you want to respond to and AI fills it out for you.
Ohh man, think of training something on your own corpus of writing over the years.
god we could probably more or less do that now…
14% of 200 == 28% of 100 == 28
You can also do 200% of 14, which I find more straightforward.
Why do you have to divide on both sides in your example with 14% of 200?
Oh shit, there I go getting along winded and get lost, yep, that should have been multiplied on the other side.
maths is the same in both case but I get it, for small numbers this is useful
Sweet, thanks Panzer of the Lake!
Teaching stats and using percentages now and again, it’s not really that useful of a tool most of the time since you aren’t usually working with an easy number like 50 (Or 10, 20, 25, etc.).
Usually what I’m doing is breaking it down into manageable parts (factors), so 6% is 5% + 1% which I can usually do in my head regardless of the number (or if 5% hard, work in increments of 1%, which I can multiply by 6).
It’s a pretty common strategy to with with factors. Just surprised how many of my students don’t know it!
I’m still doing a rule of threes either way.
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 * 50/100Where 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.
