Las Matemáticas — Mathematics

[chileno]

Originally Posted by laepelba

Another question for you all.

I team teach an Algebra class for English-as-a-Second-Language students. I am the "math specialist" and the other teacher is the "ESL specialist". Most of our students are native Spanish speakers. The other teacher knows some Spanish, although I don't remember where/how she learned it. She is not actively studying it.

Recently, I was talking about writing units on measurements that are proportional. For example, in English, if a speed is given in "meters per second", it is written as "m/s". Some of the kids were asking me about "per". I think that at some point in time, I heard something in a similar context that used "por", like if something happened once a day, it would be said "una vez por día". Is that correct or incorrect?

Anyway, I said something to some of the students about "per" in English being like "por" in Spanish. My team teacher jumped in and said, "well, it's like 'cada'. 'Each'." I suppose that makes logical sense to me, but for some reason it seems incorrect.....

So what is the correct way to give a proportional unit?

Thanks!!

It depends...

"una (vez) cada día" = "one (time)/once each day"

"una (vez) por día" = "one (time)/once per day"

"una (vez) al día" "one (time) a day"

[laepelba]

Originally Posted by chileno

It depends...

"una (vez) cada día" = "one (time)/once each day"

"una (vez) por día" = "one (time)/once per day"

So what do you say in a mathematics class about units? It "depends" on what?

[chileno]

Originally Posted by laepelba

So what do you say in a mathematics class about units? It "depends" on what?

What do you mean? I gave the possibilities to administer anything in any units you want, we are talking about intervals, don't we? Units can be related to this but you haven't talked yet about what units.

[laepelba]

Well, the units can be all kinds of different things ... m/s, miles/h, km/h, miles/sec, etc.

You said "it depends", but I'm wondering, what does it depend on? In Spanish math classes, do they teach two different scenarios? Sometimes you say "cada" and sometimes you say "por"?

[chileno]

Originally Posted by laepelba

Well, the units can be all kinds of different things ... m/s, miles/h, km/h, miles/sec, etc.

You said "it depends", but I'm wondering, what does it depend on? In Spanish math classes, do they teach two different scenarios? Sometimes you say "cada" and sometimes you say "por"?

Mph is for "each" or "per" and I am talking strictly in English

55mpg

$2.17 a gallon/per gallon

Doesn't it depends in English too?

[laepelba]

I wouldn't ever use "each" in units as a label in English. So I suppose I would never use "cada" in units as a label in Spanish, right?

[chileno]

Originally Posted by laepelba

I wouldn't ever use "each" in units as a label in English. So I suppose I would never use "cada" in units as a label in Spanish, right?

I am not sure.

For each gallon of water, pour 1 cup of bleach.

I guess you couldn't cope with that...?

Rest a little a come back with renewed. It is the mind playing tricks at you.

[laepelba]

Well, this is something that I've pondered for about a week before posting the question, so I'll continue to pursue it. If you want to stop answering, I'm sure someone else will pick it up...

The example you give (For each gallon of water, pour 1 cup of bleach.), that is typical of a science class. I'm specifically looking for math problems given strictly in the context of a math classroom. And you're describing a process, not giving a quantity with units.

In my class, I would ask something like follows:
- If light travels xxxxx miles in 8 minutes, what is the speed of light given in miles/second?

I would tell English speaking students that "per" means that the denominator is "one", and that they have to convert from 8 minutes to 60 seconds in a minute and make the denominator 1.

I can't think of an instance where I would use "each"........

[chileno]

Originally Posted by laepelba

Well, this is something that I've pondered for about a week before posting the question, so I'll continue to pursue it. If you want to stop answering, I'm sure someone else will pick it up...

Sheesh!

I didn't realize you had been pondering this for some time...

No need to become belligerent.

Originally Posted by laepelba

In my class, I would ask something like follows:
- If light travels xxxxx miles in 8 minutes, what is the speed of light given in miles/second?

In this case to express miles/seconds it usual to use "miles per second", right? The same in Spanish

The rest somebody else will have to answer it, as I am not understanding your position. Maybe when I get back to this post I will have an insight or something...

[laepelba]

It wasn't my intention to seem belligerent. Take what I said at face value. I ponder things like this before I ask....

Sounds like "por" is a better choice for what I'm looking for.......

[alx]

Hi there, here's my opinion

@laepelba
We tend to say "metros por segundo" just like you do, even though it should be "metros por cada segundo" (same happens with other x/y units), accordingly with definition of m/s, it is the distance covered by an object for each second elapsed.

I don't know exactly why we say it that way (as children we are taught this), i guess it's a bad custom of ours.

I found this at Wikipedia:

Nótese que en la rapidez, o en el valor de la velocidad, la dimensión del tiempo es inversa (m/s en lugar de m•s), por lo que la expresión «metro por segundo» significa «un metro por cada segundo», «un metro en cada segundo», o incluso «un metro dividido por segundo». No se debe confundir con «un metro multiplicado por segundo», lo cual no es una unidad de velocidad.

This is a rough traslation:
Notice that speed-wise, the time dimension is inverse (m/s instead of m*s), thus <<metros por segundo>> means <<un metro por cada segundo>>, «un metro en cada segundo», or even «un metro dividido por segundo».
This must not be mistaken for «un metro multiplicado por segundo» since that's not a speed measuring unit.

Hope it helps.
Let us know if any doubts still remain.

Regards

[laepelba]

Thanks, alx - helps a lot!

[chileno]

Originally Posted by alx

Hi there, here's my opinion

@laepelba
We tend to say "metros por segundo" just like you do, even though it should be "metros por cada segundo" (same happens with other x/y units), accordingly with definition of m/s, it is the distance covered by an object for each second elapsed.

Hi alx and laepelba:

That explanation should be the same one in English.

Maybe one tend not to think of things like this until one decides to learn another language, and that's when "idiolects* and idiotsyncracies" start to surface, in both languages.

*(term taught from pjt, I love it!)

[laepelba]

Okay, how about this one... In Geometry we talk about "conic sections": circles, parabolas, hyperbolas and ellipses.

Would the vocabulary be as follows?
Las secciónes conicas son los círculos, las parábolas, las hipérbolas, y las elipses.

[chileno]

Originally Posted by laepelba

Okay, how about this one... In Geometry we talk about "conic sections": circles, parabolas, hyperbolas and ellipses.

Would the vocabulary be as follows?
Las secciónes conicas son los círculos, las parábolas, las hipérbolas, y las elipses.

¿Por qué no "Secciones cónicas: (los) círculos, (las) parábolas, (las) hipérbolas, y (las) elipses"?

You got it.

[laepelba]

How about the word "countability" (In mathematics, a countable set is a set with the same cardinality (number of elements) as some subset of the set of natural numbers.) In Spanish, "countable" would be "contable" or "numerable", right? How about the noun form, then?

[AngelicaDeAlquezar]

My teachers never used any equivalent (we only talked about "conjuntos contables"), and although I've never seen the word used in this sense, the DRAE gives contabilidad".
I suppose it will be correct to say "la contabilidad de un conjunto", to talk about it's quality of being countable.

[laepelba]

Originally Posted by AngelicaDeAlquezar

My teachers never used any equivalent (we only talked about "conjuntos contables"), and although I've never seen the word used in this sense, the DRAE gives contabilidad".
I suppose it will be correct to say "la contabilidad de un conjunto", to talk about it's quality of being countable.

Thanks - that's what I thought. But the word "contabilidad" came in a "word of the day" email as "accounting" or "bookkeeping", and I wasn't sure if it also applied to more "pure" mathematics as "countability".

In the RAE, are you looking at: "Aptitud de las cosas para poder reducirlas a cuenta o cálculo." ?? I suppose the reason I wasn't sure about that particular definition was because it seemed to be *not* about pure mathematics.

Anyway, thanks for the answer. It's actually a word we use quite frequently, but ONLY in reference to sets of numbers.

[aleCcowaN]

rotor / rotacional = curl / rotor
divergencia = divergence
gradiente = gradient
nabla (del) = del (nabla)

[irmamar]

Un conjunto es contable o numerable si es finito.