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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

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Original poster

to point out to the teacher that a square is a rectangle?

216 replies

GooseyLoosey · 09/05/2011 15:11

Part of ds's homework was to draw on a grid 2 rectangles with a perimetre of 8cm. He drew a 3x1 oblong and a 2x2 square.

Aside from the fact these were the only possible shapes without using 1/2 squares, the teacher marked his homework as incorrect as a square was not a rectangle.

Ds (who is a perfectionist) read this and was not at all happy. He shouted "it is, I know it is, it is. Mummy, I'm right".

Would I be unreasonable to tell ds to ask the teacher why a square is not a rectangle? Or are we completely wrong and squares and rectangles are mutually exclusive?

(PS - I really don't expect teachers to always be right - God knows I am not but this teacher is the school's maths co-ordinator).

OP posts:

Nanny0gg · 10/05/2011 22:25

musicmadness

'Yep, all squares are rectangles.

I think someone mentioned this further up, but whether or not an oval counts as an oblong depends on whether you are using british english or american english as far as I know.

In british english an oblong is defined as a non square rectangle basically, so under this definition an oval is not an oblong. However, I have also seen an oblong defined as a shape with length longer than width, therefore an oval would count as an oblong as it would be an elongated circle.

In practise I think people most often use oblong to define a non square rectangle though (certainly in the UK anyway!).'

When I was at school (many years ago!) I was taught that an oval was called an oblong. That's what I would have called it. And rectangles were rectangles.
Am horrified that the teacher in the OP doesn't know that a square is rectangle though.

StealthPolarBear · 10/05/2011 22:28

no wonder people think schools ae crap at the moment

And seriously, you don't need a degree in maths/to be a teacher of maths etc to know this

FreudianSlipOnACrown · 10/05/2011 22:55

And IMO, it's not even just about knowing it. I have to admit, despite the fact that I'm doing a maths degree, I didn't know a square was a rectangle - I guess I was getting rectangle confused with oblong, I don't remember doing proper definitions - but the point is, even if I was already teaching a class, and a child told me a square was a rectangle, I would NOT just say that's wrong. I'd ask for their reasoning and discuss it, and look up the official definition of rectangle etc... And then be full of praise for him.

I really really dislike teachers (or anyone at all) who are so arrogant they cannot admit to not knowing something, or admit to being wrong.

grubbalo · 11/05/2011 08:31

I think it's a bit of a leap to go from this situation to saying that people think schools are crap at the moment! My DH is a teacher who would be happy to be told he was wrong - to be honest it's all about confidence isn't it. If you're a teacher who is happy to understand that no matter how clever you are, you are going to teach students who are cleverer, then you aren't going to be flawed by this situation. Unfortunately, like every other job in the world, there are going to be bad examples of people carrying out the job.

Plus we don't actually know what the teacher's reaction has been to this - she may have been perfectly happy to admit she was wrong in the end - we will have to wait and see.

FreudianSlipOnACrown · 11/05/2011 08:39

Fair point grubbalo. Looking forward to an update!

IntotheNittyGritty · 11/05/2011 10:42

Unless you specifically know this, it is not a common fact that everyone would immediately know the answer to so I think you are being hard on criticising the teacher.
As mentioned below, we dont know how the teacher responded

WriterofDreams · 11/05/2011 10:45

But Gritty, shouldn't a teacher know this??

Down through the years I've been really shocked at the poor maths knowledge some primary teachers have. As a supply I was once teaching statistics to a group of year 5s and they told me their teacher had taught them that the range was the highest number in a set of numbers. That's bloody basic information that a teacher should know. If ever I'm not entirely clear about a maths topic I read up on it before I teach it. Basic professionalism IMO.

xstitch · 11/05/2011 10:51

I agree with writer. While you may not know much about an area you should specifically read up on it before teaching a class on that specific subject. I would go as far as say they should a have a reference source close to hand so that if the need arises something can be looked up.

Gentleness · 11/05/2011 11:00

Who knows - maybe the teacher is kicking herself for setting the homework, has checked out her mistake and realised she is wrong already. I'm sure every teacher has said or written something on the spur of the moment while semi-distracted, only to realise it was daft. I remember returning to some marking comments when I woke up in the night with that sinking feeling and just wrote, "Sorry..." and corrected what I'd put. Helped the kid know teachers get it wrong and can apologise without covering up, and made sure the parents wouldn't crucify me for making mistakes at the next parents evening.

Maths knowledge can be pretty poor at primary level - not just the details like this case, but the fundamental understanding of progression in number which has more serious consequences. It can happen amongst the most professional of teachers who just aren't "mathematically brained" and is one of the biggest ever arguments for making sure there is a proper maths specialist on every staff to take a lead in professional development - after all, the best way of learning something is to have to teach it properly! Ok, off soapbox now.

xstitch · 11/05/2011 11:04

gentle the teacher in the OP is the maths specialist isn't she?

WobblyWidgetOnTheScooper · 11/05/2011 12:53

I do agree the teacher should've known it really (and totally agree that some primary teachers are not good enough at maths - had some absolute shockers in my DSDs' school) - but IMO that's a separate issue.

The key here is that the teacher should have looked it up and admitted that DS was correct. But as grubbalo rightly pointed out, we still don't know if that's happened or if the teacher will admit she was wrong.

Donki · 11/05/2011 21:07

Gentle - they are the maths co-ordinator. This is not the same as being a maths specialist, as some primary schools (especially small ones) may not have anyone who is mathematically minded.....

xstitch · 11/05/2011 21:38

OP how did you get on?

Gentleness · 11/05/2011 22:08

Donki - exactly! Being a co-ordinator can be as much about management skills as about subject knowledge, however ridiculous that sounds. And I've never heard of a school where the staff all get together and work out whoever is best at maths so they can co-ordinate it etc.

Anyway - hope there has been some kind of sort-out with the teacher!

HibernoCaledonian · 12/05/2011 19:42

Bump

perplexedpirate · 12/05/2011 22:23

Both a square and an oblong are rectangles because they have four right-angled corners.

The teacher is wrong and your clever DS is right.

perplexedpirate · 12/05/2011 22:24

x-post with just about everyone...

kalo12 · 12/05/2011 22:27

a square is a rectangle. tell your son to 'ask' her. Teachers are normal people you know, they are not all meglomaniac dictators. I'm sure she won't take offence!

edam · 12/05/2011 22:53

OK, I knew a square was a rectangle, but I had no idea an oblong was not the same thing as a rectangle. I thought the terms were interchangeable. What is the difference between an oblong and a rectangle, please?

Tangle · 12/05/2011 23:00

If the comments on the rest of the thread are correct, and oblong is any non-regular rectangle whilst a square is any regular rectangle - so any rectangle must also be either a square OR an oblong.

I don't think I ever tended to use "oblong" that much, or I'd have the same usage as you. Always something left to learn :)

And I want to know how the teacher reacted!

edam · 12/05/2011 23:05

Yup, me too! I vaguely remember oblong from school but have not had cause to use the word for 30 years so have no idea what one is, really, if it's not four right angles with two long sides and two short.

WobblyWidgetOnTheScooper · 12/05/2011 23:28

Any news OP?

RoadArt · 13/05/2011 00:05

Just found this on another forum. The question was Oblong or Rectangle.

"This is a problem isn't it as we are used to using rectangle for a shape with two sides longer that the other two, and square for a shape with all four sides the same length? A rectangle is a shape with 4 ninety degree angles, so a square and what we call a rectangle are both rectangles. An oblong has two sides longer than the other two sides, but still has 4 ninety degree angles. We are used to using the term square for a shape with all sides all the same length which is correct, and rectangle for two sides long and two sides short, when actually that is an oblong"

edam · 14/05/2011 23:48

Oh, OK, so an oblong is a rectangle but a rectangle doesn't have to be an oblong. I think!

confuddledDOTcom · 15/05/2011 01:00

Try turning it around. There are two types of rectangle, an oblong which has two pairs of sides and a square which has all the sides the same length.

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