Long division
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@Zecc said in The Official Funny Stuff Thread™:
@error_bot said in The Official Funny Stuff Thread™:
It took me somewhat longer than necessary to understand what's going on in this, because I learned to do long divisions with the numbers laid out differently: https://en.wikipedia.org/wiki/Long_division#Eurasia
127|4 −124|31,75 30 −28 20 −20 0
I actually didn't put much attention to the numbers when I posted this. I only looked at the layout.
Now I'm trying to make sense of it, and I honestly can't.Here's how I've learned to do it:
I suppose you could say I skipped an initial step of setting the first digit to zero, subtracting zero from 1, and lowering the 2.
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Great, now I can't change this to another thread category?
Long divisions are hilarious!
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The way I learned to write it is almost like yours:
127 : 4 = 31.75 -12 -- 7 -4 - 30 -28 -- 20 -20 -- 0
I never understood the English way to write it or why there are radix signs in it.
E: Eh, the Wikipedia page has exactly this in it. So much for redundancy.
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4 / 127 \ 31.75 120 30 --- 7 4 1 - 3.0 2.8 0.7 --- 0.20 0.20 0.05 ---- 0
I don't think we ever really did long division into decimals though, just integer with remainder.
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I'd forgotten how to do this. Couldn't even tell you how I was taught.
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@loopback0 said in Long division:
I'd forgotten how to do this. Couldn't even tell you how I was taught.
I was taught like this:
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@Zecc said in Long division:
Long divisions are hilarious!
127 : 4 = 31.75
It's not even
long
division. To get a real number, at least one of the operands must be real!
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@Applied-Mediocrity Good joke.
I dig it.
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@Vault_Dweller said in Long division:
@loopback0 said in Long division:
I'd forgotten how to do this. Couldn't even tell you how I was taught.
I was taught like this:
Common Core in action.
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Here's how I learned it:
It's nice because you don't have to guess where to put decimal separator.
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@Gąska You don't have to guess with @Zecc's method, either. You put it in the quotient when you start using digits to the right of the decimal separator in the dividend (whether it's explicitly there or implied at the end).
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@Khudzlin easier than that. When the remainder is smaller than the divisor, you add a 0 to the remainder and a comma (YES IT'S A COMMA) or a 0, if after the decimal separator, to the quotient.
If you're messy and can't write in neat columns like me, it's easier at least.
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@admiral_p said in Long division:
If you're messy and can't write in neat columns like me, it's easier at least.
You're doing math on non-grid paper!?
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@Gąska said in Long division:
You're doing math on non-grid paper!?
Of course! Grid paper is for drawing doodles.
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@Khudzlin said in Long division:
@Gąska You don't have to guess with @Zecc's method, either. You put it in the quotient when you start using digits to the right of the decimal separator in the dividend (whether it's explicitly there or implied at the end).
Still more work than just putting it right above the dividend's decimal point.
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@admiral_p You won't catch me handwriting a decimal point instead of a comma, anymore than you'll catch me forgetting to put a bar through a 7.
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@Khudzlin the funny thing is that commas are an ISO standard. And it's also better to look at.
1 023 004,75
With spaces for thousands separators (or maybe apostrophes).
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@admiral_p Also, currency signs belong after numbers, like all other units.
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@Khudzlin said in Long division:
forgetting to put a bar through a 7
I learned to do that when I traveled thru Europe after graduating college. Back then, many places you had to write down the phone number and hand it to the operator (I was calling home - collect. It was an semi-emergency) When I got a "they won't accept a collect call" I was confused (actual number ended with 0137). I figured it out shortly afterwards. Been doing it ever since.
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@dcon They didn't confirm the number orally?
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@Khudzlin said in Long division:
@dcon They didn't confirm the number orally?
It was 1985. I don't remember things that long ago! (and they must not have, because I would have caught that)
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@PleegWat said in Long division:
I don't think we ever really did long division into decimals though, just integer with remainder.
I think that’s what in my school, we were taught it that way at first: 127 divided by 4 gives 31 and a remainder of 3, or possibly 127 divided by 4 gives 31¾. Probably in the next year, or whenever it was that we were taught about decimals, I’m sure long division was explained with those as well. This was in the early ’80s, so if you went to primary school after that, you were probably taught a dumbed-down version
@dcon said in Long division:
@Khudzlin said in Long division:
forgetting to put a bar through a 7
I learned to do that when I traveled thru Europe after graduating college. Back then, many places you had to write down the phone number and hand it to the operator (I was calling home - collect. It was an semi-emergency) When I got a "they won't accept a collect call" I was confused (actual number ended with 0137). I figured it out shortly afterwards. Been doing it ever since.
There’s a strange kind of similar stupidity in this country regarding the number 4 when hand-written: I normally write it looking like this: 4. The way you’re generally taught to write in schools here, though, is much like this: Ч. If I had a euro for each time I’ve had people mistake my 4 for a 1, I’d be … um … well, not very rich at all, but slightly wealthier than I actually am.
And the reason I began writing 4 like that is because once upon a time, I discovered that English people tended to mistake the Ч-shaped 4 in my postal code for an upper-case U.
All this said, I myself always have a little trouble recognising German hand-written 1, as it tends to look like an italic A without the horizontal bar.
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@Gurth said in Long division:
All this said, I myself always have a little trouble recognising German hand-written 1, as it tends to look like an italic A without the horizontal bar.
Or a ⋀ symbol, which makes even moderately complex math quite annoying…
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@Gurth said in Long division:
I normally write it looking like this: 4.
Same, people always confused them with 9s though, never a 1.
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@Zecc said in Long division:
@Gąska said in Long division:
These are both terrible ways to do long division, especially if you need to extend the dividend to keep dividing further (although the color-coding in the first one helps a little bit).
The method shown in the XKCD comic is the right way:
The decimal separator is easy to put in the right place (or to move, if needed), and it's easy to add further decimal places as the precision of the calculation increases.
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This is how I was taught.
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@djls45 I'm not taking maths advice from an Brit or American.
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@admiral_p said in Long division:
@djls45 I'm not taking maths advice from an Brit or American.
Americans don't have maths, so you'll never have to. (We have math or mathematics.)
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Wow, all this has taught me is that other countries are shit at teaching maths.
I mean, wtf is that bullshit with putting the divisor to the right? Just makes it all look weird.
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@Dragoon you know that those awards are all coopted by the plutojudaic masonry.
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@Snooder said in Long division:
Wow, all this has taught me is that other countries are shit at teaching maths.
I mean, wtf is that bullshit with putting the divisor to the right? Just makes it all look weird.
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@Tsaukpaetra I meant root, sorry.
Basically, whytf does it look like this:
4√127
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I had to go look it up on swedish Wikipedia to refresh my memory of how it worked. And I got this nice picture which is how I was taught it:
So for 764 / 4 start from left:
Times 4 fits in 7: 1. Remainder: 3.
Times 4 fits in 36: 9. Remainder 0.
Times 4 fits in 4: 1. Remainder 0.
Equation done.
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@topspin said in Long division:
@Tsaukpaetra I meant root, sorry.
Basically, whytf does it look like this:
4√127IDK. Whenever I write it it looks like this:
But it's very difficult to represent that digitally...
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@Tsaukpaetra Yeah, that’s a square root. It should read
127 : 4
.
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Wolfram says it doesn't know what the proper name for it is either.
My conspiracy senses are beeping...
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@djls45 said in Long division:
@Zecc said in Long division:
@Gąska said in Long division:
These are both terrible ways to do long division, especially if you need to extend the dividend to keep dividing further (although the color-coding in the first one helps a little bit).
With mine, you just do one -0 and then you have all the space you want. I agree that @Zecc's method sucks.
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@Gąska said in Long division:
@djls45 said in Long division:
@Gąska said in Long division:
This is a terrible way to do long division, especially if you need to extend the dividend to keep dividing further.
With mine, you just do one -0 and then you have all the space you want.
But with yours, you lose the alignment of the dividend with the quotient, so it's harder to review your work.
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@djls45 huh?
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@Gąska said in Long division:
@djls45 huh?
By not putting any lines to show which position lines up with which, it can be harder to follow, especially where the colon and divisor get in the way or where a lot of decimal places turn out to be needed for the calculation.
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@Gąska said in Long division:
Looks like 4th root to me.
You wrote word for word what I actually wrote in a new post I didn't get to submit.
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@Gąska said in Long division:
I agree that @Zecc's method sucks.
It's how I was taught, and I did think it sucked at the time.
Am I the only one who omitted the subtractions?
The lines were there for illustration purposes, btw. We generally didn't write them.
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Again, lads. You add a 0 or a comma when the remainder is too small. All this talk of columns only works if you're tidy. When you're a kid in school learning how to do long divisions you're not tidy anyway. When you become tidy enough, you can already use calculators.
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@Gąska said in Long division:
@topspin said in Long division:
@Tsaukpaetra Yeah, that’s a square root.
Looks like 4th root to me.
You are right, of course.
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@admiral_p said in Long division:
Again, lads. You add a 0 or a comma when the remainder is too small. All this talk of columns only works if you're tidy. When you're a kid in school learning how to do long divisions you're not tidy anyway. When you become tidy enough, you can already use calculators.
Lol, the beauty of knowing long division is that you dont need a calculator.
Most exams I took, we weren't allowed to use one. Even if you were calculating 22/7, you just did it and showed your work out to however many decimal places the test asked for.
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@Snooder said in Long division:
Lol, the beauty of knowing long division is that you dont need a calculator.
You get different questions if you have a calculator allowed to if you you can't bring one in. In particular, when a calculator is allowed there's usually less focus on the mechanics of actual calculation and more need for either insight (no calculator helps there!) or processing a reasonable amount of data (which it would be excessively laborious to do without at least a calculator to provide assistance).