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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

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:
Original poster
GooseyLoosey · 09/05/2011 15:26

I am so glad that you all agree with us. I am feeling very self-righteous now!

OP posts:
grubbalo · 09/05/2011 15:26

I really feel for you and your son Goosey - as a mathematician I'm not sure I'd be able to let it go... I just know I'd have to go and point it out... although guess is worth checking that she didn't specify rectangles that weren't squares...

My DS starts school in September and I get the feeling I'm going to be a nightmare parent - luckily DH a teacher so hopefully he'll be able to reign me in a bit...

StewieGriffinsMom · 09/05/2011 15:27

This reply has been deleted

Message withdrawn at poster's request.

Original poster
GooseyLoosey · 09/05/2011 15:29

She didn't specify no squares - I have seen the instructions!

As a perfectionist, ds is having trouble letting it go too.

OP posts:
grubbalo · 09/05/2011 15:33

Stewie - rectangles are a subset of parallelograms - parallelograms are shapes with 4 sides, where both sets of opposite sides run parallel to each other. Rectangles fall into this "family" and are the special case where all the angles are right angles.

So squares are a subset of rectangles which are a subset of parallelograms. Oh man, I haven't thought about this for a long time!! Love that there have been so many replies about this subject in such a short space of time!!

Fennel · 09/05/2011 15:33

I've been in to school several times to challenge the maths homework marking (I bet they just LOVE me :-) ). I don't expect all the teachers to be totally brilliant at maths, we happen to be quite a mathematically oriented family and obviously not all primary school teachers will have that enthusiasm for maths, but I would expect the school maths coordinator to get this right.

in our school, when I have gone in and challenged, they have agreed with us. I do it quite politely and we all pretend it must have been falsely marked, by mistake, etc. to save face.

IgnoringTheChildren · 09/05/2011 15:34

Your DS is correct and the teacher should be made aware that a square is a type of rectangle! How to manage this without pissing the teacher off and making him/her hate your DS for the rest of the year is the real question here! Wink How old is your DS? Could he take in a print out from a reputable website to show the teacher? Would he be able to approach the teacher in a way that won't get them on the defensive/wind them up?

I'm a science teacher and have had a few cases where I've 'challenged' pupils to prove me wrong when they've disagreed with me - so long as it's handled well on both sides it can be quite a fun approach to education! However I can easily imagine colleagues of mine taking this less well Hmm...

Still think that the teacher needs to be told though! Grin

Original poster
GooseyLoosey · 09/05/2011 15:34

Grubbalo - I think my ds would love the way you think! He loves maths.

OP posts:
StewieGriffinsMom · 09/05/2011 15:37

This reply has been deleted

Message withdrawn at poster's request.

Sillyness · 09/05/2011 15:37

I'm a primary teacher (and not the most confident at maths), but before teaching things I double check and if a child queries me, I check again.

After all, if this was a test, we(teachers) would be looking for them to get the best possible score and would appeal this marking!

grubbalo · 09/05/2011 15:38

I am just hoping my DS's love maths the way your son does - as you can probably tell, I did too! Please let us know how it goes!

IgnoringTheChildren · 09/05/2011 15:38

x-posted with loads of people! Your DS definitely shouldn't let it go! Grin

whoneedssleepanyway · 09/05/2011 15:39

I distinctly remember from school:

ALL SQUARES ARE RECTANGLES BUT NOT ALL RECTANGLES ARE SQUARES

Smile
DeWe · 09/05/2011 15:45

A square is a regular rectangle. A rectangle is a specific quadrilateral (sp?)
eg. You can have hexagons with 6 sides of different length, but in a regular hexagon you have 6 sides of equal length, and all the angles are the same too (120deg)
Just as a circle is a specific type of ellipse (oval).
I'd write under his drawing: "A square is a type of rectangle", as though you were writing it for him, then if the teacher challenges it, she knows that it comes from you not him.

OryxCrake · 09/05/2011 15:47

Yep - a square is a type of rectangle. Don't let the teacher undermine your clever DS!

Ariesgirl · 09/05/2011 15:50

Ahem. As a former primary teacher I always taught that a square has 4 sides of equal length and 4 right angles, a rectangle had 2 pairs of equal sides (you know what I mean) and 4 right angles, and that both were regular quadrilaterals.

minipie · 09/05/2011 15:51

Your DS is right, the teacher is wrong.

However, not many teachers take too kindly to being corrected by an 8 year old (I speak from bitter experience).

Ariesgirl · 09/05/2011 15:51

Or else there would be an awful lot of confused children and parents and teachers.

RitaMorgan · 09/05/2011 15:51

If your ds looked it up beforehand to check it was right, then I think it totally undermines his good work for the teacher to tell him it's wrong. If it was me I would point it out to her - I like the idea of letting your ds take a print out with the information in for her.

Anice · 09/05/2011 15:52

a square is a type of rectangle

harecare · 09/05/2011 15:54

A square is definitely a rectangle, definitely point it out.

JoanofArgos · 09/05/2011 15:56

I think the rights and wrongs of squares and rectangles aside, you should not take it up with the teacher, as it was obvious what she wanted them to do, and drawing a square so that you can go 'aaaaah but do you not see?' is precious and irritating tbh!

Tell your son yes, he's quite right, but language is slippery sometimes and generally when people refer to rectangles they do mean two sides longer than the other two.

Fennel · 09/05/2011 15:56

With a bright enquiring child, you might as well teach them from this point forward that you learn general rules in the education system, and these rules are not always utterly correct, and as you go on you'll learn new more complex rules to override the simpler rules. It happens a lot in Maths, all the time in Physics, and it's a way of showing how the primary school teacher might teach this simplified (incorrect) way of distinguishing between a square and a rectangle, and yet it not be actually right once you look closely.

if that makes sense...

senua · 09/05/2011 16:00

I think you ought to speak to the teacher. Otherwise she will contine to make this mistake and pass it on to future schoolchildren forever.

Insomnia11 · 09/05/2011 16:02

Can you illustrate this in Venn Diagram form? :)

How does "oblong" fit into this? How about a rhombus?

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