View previous topic | View next topic

Semantic difficulty

Page 6 of 7
Goto page Previous  1, 2, 3, 4, 5, 6, 7  Next

Dix
1374417.  Sat Feb 13, 2021 10:04 am Reply with quote

Brock wrote:
Dix wrote:
That's why I added "if describing a maths puzzle".
If you have never encountered any such puzzle, yes, I can see why you'd need clarification as to what was meant.


Even if it was describing a maths puzzle, I'd have assumed that "three hotels = 12" represented a picture of three hotels, followed by the symbols " = 12". The fact that the English words "three hotels" were used on the left-hand side, rather than any mathematical symbols, would have led me to that conclusion.

Why would someone write "three hotels" if it wasn't actually a picture of three hotels?


Because all details aren't always given in an informal description?
Maybe the writer didn't actually remember precisely what the puzzle looked like, maybe the details were thought unimportant because it was just a description of "that kind of maths puzzle that has drawings in it".
Why would anyone waste time on describing all details correctly if it was just meant to give a broad indication?

It's not as if you were asked to solve a particular puzzle based on the description.

 
Brock
1374420.  Sat Feb 13, 2021 10:53 am Reply with quote

Numerophile wrote:

[Edit: in fact, I see from a larger version that as well as the two trees in the last picture, there are also eight tulips, whereas there were only two in the earlier pictures. So why doesn't it count as 40 rather than 20? I conclude that the problem is unanswerable; knowing that 1 house + 1 tree + 2 tulips = 10 doesn't allow you to deduce any value for 1 house + two trees + 8 tulips.]


After looking at the pictures carefully, I note that there are actually four tulips in the first picture; and while there may appear to be only one house in the second picture, there are two chimney-pots sticking up, which I presume is meant to suggest a second house behind the first one. So the logic appears to be:

1 house + 1 tree + 4 tulips = 10
2 houses + 2 trees + 8 tulips = 20

How on earth anyone is supposed to guess that from a cursory inspection of the puzzle, I've no idea.

Furthermore, it casts doubt on the previous contention that the symbols are meant to act as algebraic variables. How is it possible to superimpose one algebraic variable on another one?

 
Dix
1374425.  Sat Feb 13, 2021 11:34 am Reply with quote

Brock wrote:
Numerophile wrote:

[Edit: in fact, I see from a larger version that as well as the two trees in the last picture, there are also eight tulips, whereas there were only two in the earlier pictures. So why doesn't it count as 40 rather than 20? I conclude that the problem is unanswerable; knowing that 1 house + 1 tree + 2 tulips = 10 doesn't allow you to deduce any value for 1 house + two trees + 8 tulips.]


After looking at the pictures carefully, I note that there are actually four tulips in the first picture; and while there may appear to be only one house in the second picture, there are two chimney-pots sticking up, which I presume is meant to suggest a second house behind the first one. So the logic appears to be:

1 house + 1 tree + 4 tulips = 10
2 houses + 2 trees + 8 tulips = 20

How on earth anyone is supposed to guess that from a cursory inspection of the puzzle, I've no idea.

Furthermore, it casts doubt on the previous contention that the symbols are meant to act as algebraic variables. How is it possible to superimpose one algebraic variable on another one?


They are deliberately trying to trick you. Not you specifically, of course, but all the would-be solvers. That generates discussion, and people share the puzzles trying to outsmart their friends. They have evolved from fairly straight problems where the only trap would be going from only addition and subtraction to also having multiplication (and operator precedence) in the last line to having ever more weird little details that "counts" (as it were).

Sometimes they (or other types of puzzles and quizzes) come with captions such as "only 5% of people will get this right".

What they're getting out of doing this isn't clear; maybe it ties on to some kind of advertisement revenue being generated by number of "likes" or the number of times it gets shared.

In any case, they're annoyingly popular. I just ignore them.

 
Numerophile
1374434.  Sat Feb 13, 2021 1:18 pm Reply with quote

Brock wrote:
After looking at the pictures carefully, I note that there are actually four tulips in the first picture; and while there may appear to be only one house in the second picture, there are two chimney-pots sticking up, which I presume is meant to suggest a second house behind the first one.


You are quite right. I see that it is in fact two copies of the first picture, stacked (almost) on top of each other. So I suppose we must allow their answer.

But how anyone would be able to make that out, if they were trying to do the puzzle on a phone, I don't know.

 
Brock
1374435.  Sat Feb 13, 2021 1:33 pm Reply with quote

Numerophile wrote:
Brock wrote:
After looking at the pictures carefully, I note that there are actually four tulips in the first picture; and while there may appear to be only one house in the second picture, there are two chimney-pots sticking up, which I presume is meant to suggest a second house behind the first one.


You are quite right. I see that it is in fact two copies of the first picture, stacked (almost) on top of each other. So I suppose we must allow their answer.


It was only after examining some of the other puzzles that I realized that two stacked copies of a picture represent double the value of a single copy. (I don't know if more than two stacked copies are allowed.)

So in this system, there are apparently two ways of representing multiplication; by stacking and by using the "x" operator. One is entirely graphical, the other uses a conventional mathematical symbol.

I can't help feeling that it's not a great way of teaching arithmetic or algebra. One would hope that their conventions would be consistent.

Quote:
But how anyone would be able to make that out, if they were trying to do the puzzle on a phone, I don't know.


Most of the other doubled graphics were clearer (e.g. one railway carriage behind another). That one was just confusing.

 
Leith
1374437.  Sat Feb 13, 2021 1:50 pm Reply with quote

Brock wrote:
I can't help feeling that it's not a great way of teaching arithmetic or algebra. One would hope that their conventions would be consistent.

Quote:
But how anyone would be able to make that out, if they were trying to do the puzzle on a phone, I don't know.


Most of the other doubled graphics were clearer (e.g. one railway carriage behind another). That one was just confusing.

I quite agree. That particular example and its ilk are deliberately designed with subtleties to catch out the unwary. That's fine for a mildly diverting internet puzzle (if better rendered than the example I posted), but doesn't seem at all helpful to me as a teaching aid (not that I have any particular expertise in teaching children).

I think the simpler version that Awitt describes, lacking the additional complexity of small variations in the glyphs could have more useful potential for teaching.

 
Dix
1374440.  Sat Feb 13, 2021 2:59 pm Reply with quote

I'd certainly expect a teacher to stick to the "regular" ones.

As it is, since the original puzzle description was vague, we simply don't have that information.

 
CB27
1374601.  Mon Feb 15, 2021 10:11 am Reply with quote

Dix wrote:
As it is, since the original puzzle description was vague, we simply don't have that information.

Argh no!!!! We've gone all the way back to the start....

 
barbados
1374609.  Mon Feb 15, 2021 11:07 am Reply with quote

And to think we were sooooooo close

 
Brock
1375423.  Tue Feb 23, 2021 10:14 am Reply with quote

[As this topic falls squarely into the category of "nerdy over-examination of semantics", this would seem to be the appropriate thread.]

The context is the Government's "road map" for easing the lockdown in England, which puts "no earlier than" dates on several stages.

post 1375400

dr.bob wrote:
And yet they've imposed limits on which date that will happen by.


post 1375404

Brock wrote:
No, they've imposed no limits on when it will happen by. These are "no earlier than" dates, not "no later than" dates.


post 1375405

crissdee wrote:
Which is still surely a limit, just a retrograde limit. "No earlier than" is just as much of a limit as "No later than".


post 1375406

Brock wrote:
Yes, but that's not a limit on when it will happen by. In the context of time, "by" means "no later than".

If you lend me a tenner, and I say "I'll pay you back by next Wednesday", that means "no later than next Wednesday". I think you'd have a right to be rather disgruntled if I chose to pay you back in three months' time!


post 1375417

dr.bob wrote:

crissdee wrote:

"No earlier than" is just as much of a limit as "No later than".


Quite so.


I have no disagreement on that point. "Step 2 will happen no earlier than 12 April" is certainly a limit on when step 2 will happen. My issue was whether "step 2 will happen no earlier than 12 April" is a limit on when step 2 will happen by.

The COED says that the preposition "by" is used to indicate the end of a time period, as in my earlier example of "I'll pay you back by Wednesday". Saying that step 2 will happen no earlier than 12 April isn't putting any sort of limit on the end of a time period. It's putting a limit on the beginning of a time period.

So I don't see how you can say that "step 2 will happen no earlier than 12 April" puts a limit on when step 2 will happen by. "Step 2 will happen no later than [date]" would put a limit on when it will happen by.

 
dr.bob
1375428.  Tue Feb 23, 2021 10:49 am Reply with quote

I see your point, and I completely agree. If you remove the word "by" from my original post, my point stands much more coherently.

Thank you for the correction.

 
Brock
1375437.  Tue Feb 23, 2021 11:49 am Reply with quote

Good. One of the easier issues to sort out!

 
dr.bob
1375483.  Wed Feb 24, 2021 4:59 am Reply with quote

Apologies for that. Maybe we should argue for a few more pages yet, just for tradition if nothing else :)

 
Brock
1375484.  Wed Feb 24, 2021 5:25 am Reply with quote

I did spend some time thinking about whether any sensible interpretation could be given to "step 2 will happen by no earlier than 12 April".

It would presumably mean that the latest date on which step 2 will happen is no earlier than 12 April - i.e. that step 2 will happen on or before some unspecified date in the future, which may fall on 12 April or later. In other words, it's equivalent to saying that step 2 may happen on any future date whatsoever!

 
Brock
1375515.  Wed Feb 24, 2021 9:45 am Reply with quote

Apropos of this discussion, it really doesn't help when I read reports like this in the media:

https://www.theguardian.com/world/2021/feb/24/the-forecasts-that-spooked-boris-johnson-into-slowing-exit-from-lockdown

"On Monday, Boris Johnson announced his roadmap for lifting all Covid restrictions by 21 June..."

He did no such thing. In fact his roadmap made clear that all Covid restrictions would not be lifted until 21 June at the earliest.

When the people reporting the news can't even use the preposition "by" correctly, what hope is there for the rest of us?

 

Page 6 of 7
Goto page Previous  1, 2, 3, 4, 5, 6, 7  Next

All times are GMT - 5 Hours


Display posts from previous:   

Search Search Forums

Powered by phpBB © 2001, 2002 phpBB Group