Confession: I Hate Drawing Graphs

Shocker! Emma, the girl who loves maths, hates drawing graphs. This includes: cumulative frequency curves, histograms, graphs of parametric equations, roots of unity, and those log ones from C2 chapter 10.

Students are always surprised to find out there's an aspect of maths I find boring. They exclaim, "but you're a maths teacher!" Well, the nicer ones do. The not-so-nice ones exclaim, "but you're a massive nerd!"

I have a huge problem with this. Think of your music teacher from school. They loved music, didn't they? Do you think they loved all types of music? Classical, rap, indie, ska, dubstep, One Direction? Probably not. You wouldn't be surprised if you found out there was a genre of music they hated.

Think about an art teacher. They love art. But in their house, would they hang impressionists, surrealists, er... etc... on their walls? Would they love every medium, every era, every subject? Of course not. If they did, you would probably think less of their love of art. "Proper" art lovers usually know what they like, and are dismissive of, or even angered by, artwork they don't like.

So why shouldn't mathematicians be the same? And more importantly, why shouldn't our students see this? I let my students know when we're studying a bit of maths I'm not interested in. Maybe this puts them off it. But who cares? Of course, when my favourite bits come up, I make that known too. I also encourage students to have favourites in maths. I like my students to feel they have a specialism. It makes them feel good when that topic comes up. I want them to see mathematics as being similar to music and art: subjective.

Do you admit to students that there are things in maths you don't enjoy?

Emma x x x

When Will I Use Algebra in Real Life?

There is one question my students ask me that I hate far more than all others. Far more than "Why are you just a teacher?" and "Do you have a boyfriend? What's his name? What's his job..." etc.

That question is: "When will I use simultaneous equations/ the laws of indices/ completing the square in real life?"

A good maths teacher, of course, would have a bank of answers to such questions. "Satellite dishes are in the shape of a parabola!" etc. Urgh.

Even though I do happen to know a few applications of algebraic principles to "real life" (picture me making air quotes with my fingers), I never tell these to my students. I refuse. 

First of all - real life? I'm sorry, are my maths lessons not real? When you enter room 204, are you entering some kind of alternate universe? Is a  maths lesson merely a state of mind? Some kind of lucid dream that looks real and feels real, but can't possibly be real because instead of English the teacher is speaking in an alpha-numeric jumble?

Secondly, where did students (and, for that matter, teachers) get the absurd idea that everything one learns has to have some kind of practical "use"? Can't we simply enjoy learning maths for its own sake? Does everything we do have to have a useful purpose? What kind of depressing life would that be?

Maths is beautiful. It is deep and interesting. It is a language. It is an art. It is a self-contained world with its own rules, patterns, and mysteries. So don't try to spoil my beautiful maths with your ugly "applications". 

I will leave you with some profound quotes from mathematician G H Hardy: 

"Pure mathematics is on the whole distinctly more useful than applied. For what is useful above all is technique, and mathematical technique is taught mainly through pure mathematics". 

“Imaginary’ universes are so much more beautiful than this stupidly constructed ‘real’ one; and most of the finest products of an applied mathematician’s fancy must be rejected, as soon as they have been created, for the brutal but sufficient reason that they do not fit the facts.”

"I have never done anything 'useful'. No discovery of mine has made, or is likely to make, directly or indirectly, for good or ill, the least difference to the amenity of the world."

Of course G H Hardy was wrong with that last one - his work was actually widely applied to genetics and thermodynamics. But the point is, that wasn't why he did it. And he didn't need these applications as motivation for producing this work.

Do you agree with me or are you someone who sees maths as a "tool" with which to get things done?

Emma x x x

7 Habits to Get Your Year 7s into

(Substitute "year sevens" with "seventh graders" if you're American, "S1s" if you're Scottish, or "first years" if you're posh/old/a wizard).

Year 7s are so cute, aren't they? So eager to learn, so willing to please. Some are actually shorter than me, which is nice. By Christmas they'll have had their growth spurts and be taller than me. That's why I like this term. (FYI if you want a mental picture of me, I'm 150cm tall, 50kg, and look a bit like Garth from Wayne's World but slightly more feminine).

The thing with year 7s is that they are lovely little blank slates. They're a fresh batch of play-doh just waiting to be moulded. At my academy, we keep our classes throughout their school career. So it's important that you get your year 7s into good habits early on, to make your life easier later.

Here are the good habits I'd like to get my year 7s into:

1) Leaving the answer as a fraction

To some students, an answer of 3/5 doesn't look finished - because you haven't actually carried out the division. They would much rather put 0.6 because it looks like a proper answer. We need to stamp this out! Fractions are infinitely superior to decimals. The use of fractions should be encouraged from day one. Don't you just hate A level students who convert all their fractions to decimals? Think ahead, teachers!

2) Lining up the equals signs

Some teachers are very anal about this and I admit I'm not really one of them. But it does make algebra look a lot more beautiful when there is neat line of =s down the page.

3) Drawing margins

Why do maths exercise books not have margins pre-printed like all the other exercise books?! It drives me mad having to remind students to draw margins every day. It's amazing how some of them still forget - even my top set year 11s! We need to try some Pavlovian conditioning to get them to automatically reach for a ruler and pencil as soon as they open their books.


4) Drawing diagrams

To solve any geometrical problem, the first step should be to draw a diagram. This is something good mathematicians do automatically. I don't know which is the cause and which is the effect, but it's worth getting our students into this habit.


5) Resilience

Perhaps the most important characteristic of a mathematician is resilience. Try something. If it doesn't work, try something else. Don't tippex out your first attempt. Don't sit there with a blank page because you're scared of writing something that's wrong. If we can instil this attitude into our youngest students, they will grow up to be good mathematicians, whatever their attainment level.


6) Using a calculator properly

Calculators are great. I can honestly say I haven't done bus-stop division with pen and paper for a good 10 years. Because I own a calculator. My computer has a calculator. My phone has a calculator. Even my tape measure has a built-in calculator. Don't diss calculators. However, some students become instantly stupid as soon as they pick one up. They don't question whatever answer it spits out. Students need to be taught to estimate the answer first to check if it's roughly right. Also, calculators are really sophisticated these days, and for example you can type in the entire quadratic formula in one go without pressing equals in between or using complicated nested brackets. Teach students how to do this. Teach them about the magical s<=>d key. Explain how the fraction key works. Get them to make frequent use of the "ans" key. And most importantly, get them to buy their own and bring it in every lesson. But make sure it's a Casio! (Sorry Sharp, but you make my life so difficult. Please stop making calculators.)

7) Taking pride in their exercise book

That's "jotter" if you're Scottish. Or "notebook" if you're American. (Or "parchment" if you're a wizard).
When an exercise book gets filled up, students are supposed to keep it. What do most students do? Throw it away. How awful is this? The problem is that many students see their exercise book as the place where they do work, not the place where they write down things to help them understand. Also some books are just horribly messy! I find that if your work is neat, you take more pride in your book, and hence you put more effort into your work. I know presentation is not about learning and hence presentation-focused comments is considered ineffective marking, but I think good presentation does lead to better learning.

Those are my personal picks. Are there any you would like to add?

Emma x x x

What is x?

How do you introduce "x" to your students?

I'm guessing you start teaching informal algebra in this kind of way:

10 + ? = 20

Where the question mark obviously represents the mysterious-sounding "unknown". Except it's not really unknown, because it's obviously 10.

Eventually you replace the question marks (or empty boxes) with letters. Not just the letter x, obviously, but you have to admit x is a popular one.

In this number sentence, what is x? I don't mean what is it's value, I mean, what is it?

2x + 4 = 12

It's an unknown. It is a number that definitely exists and has one particular value which at this very moment is unknown to us but in a matter of seconds will be completely known. Two quick steps and we and x will be on first-name terms.

In this number sentence, what is x?

2x + 4 = y

Suddenly, x is no longer an "unknown". It is a "variable". Meaning, its identity is still a secret, but it's not one specific number, it could be any (any any?) number in the world.

2x + 4 = y and y = 5.

Now, suddenly, although x is a variable, it has been forced to stop varying, and simply be unknown.

Can you see how the dual nature of x (or any letter really) could be very confusing for students? If students think of a letter as representing one particular number (even if they realise that number can change on a daily basis), this might hinder them when it comes to studying linear graphs, or functions.

Maybe we should try to introduce x as a variable instead of an unknown. Think about how you could do this, perhaps with your brand new, untainted year sevens with their clean-blanket-of-snow brains.

Let me know how you get on,

Emma x x x

What is a Regular Quadrilateral?

Have you missed me? It's been over a whole glorious month since I last posted. I've been lying on my sofa reading nineties teen romance novels and leaving the house only to visit Ikea for free tea and to pretend I live there. 

But anyway, I'm back and have I got a mathematical ponderance for you!

First, grab a piece of paper and a pen (or open a notepad file, for the more evolved among you) and write down (type) the definition of regular (as in, a regular polygon). 

Done? OK. Hands up who wrote this:

"All the sides are the same length".

And hands up who wrote this:

"All the sides are the same length and all the angles are equal".

Did any of you just write this:

"All the angles are equal".?

A more important question, perhaps, for teachers, is this: what do you tell your students?

Now another little exercise for you. Is this statement always, sometimes, or never true:

"If a polygon has all equal sides then all of the angles must be the same size".

Let's think for a moment. We know it is true for triangles, although you might not be able to prove it, or even justify it, beyond the fact that your Year Five teacher told you it was true during a particularly soul-crushing numeracy hour. We have also always assumed it was true for "big polygons" like octagons, decagons, etc. But is it true?

There is one type of polygon for which the statement is definitely not true. Quadrilaterals. Sorry if the title spoiled this major reveal for you. A square is equilateral and equiangular. However, a rhombus is equilateral but the angles are not all the same size. 

OK, here's another one for you:

"If a polygon has all equal angles, then all of its sides must be the same length". Always, sometimes or never true?

Again, think about triangles first, and then think about hexagons etc. Can you prove your conjectures?

Again, the statement is clearly false for quadrilaterals. A rectangle is equiangular but not equilateral. 

So what is a regular quadrilateral? Is it a square, a rhombus, or a rectangle?

My initial thought (because I admit, I didn't actually know the correct answer), was that a rectangle is regular. I thought this because geometry mostly comes from Greece, and in Greece, they're mostly bothered about angles. Hence the word polygon: "poly" meaning many and "agon" meaning angles. So a hexagon is literally a shape with six angles. In the UK, we're more likely to say a hexagon is a shape with six sides. So I thought a regular polygon would mean a shape with regular angles. 

However a quick tussle with my favourite search engine revealed that a regular polygon must be both equilateral and equiangular. 

I'm ashamed to admit I think I might have taught students that regular just means equilateral. Or, even worse, I think I might have even implied that equilateral shapes were always equiangular! It's funny how such a simple little definition can be messed up because you think you understand it perfectly (after all, I was taught it in year five). Maths teachers like me need to make sure we are completely clear about these things. Maths doesn't leave much room for error, and these definitions need to be water-tight. 

On that note, have a good first day at school!

Emma x x x 

PS I am of course talking about convex regular polygons. Non-convex (star) polygons are of course a whole other kettle of fish! 

Is Zero a Factor of Zero?

Inspiration for this post came from an unlikely source: a bottom set year seven class and a non-specialist maths teacher. He was teaching them factors, and was asked by a student, "is zero a factor of zero?"

This question would have just about made me explode with excitement. I think my colleague's reaction was a bit different. He is a humanities teacher by trade, so naturally he was very good at fobbing them off with an answer that sounded impressive without actually answering the question.

This colleague has obviously been working with me for too long now, because after this lesson he came and asked me the same question, because he was actually interested in the answer. I even caught him reading my post Is Zero a Square Number?  at lunchtime. He's one of us now.

So, is zero a factor of zero? Well, as is often the case in maths, the answer is: it is if you want it to be.

It all depends on how you define a factor. Here are some possible ways.
For n and m natural numbers, n is a factor of m if:
1) n divides m with no remainder.
2) n x p = m, where p is a natural number.

[Side note: obviously natural numbers have negative factors too, and factors can be defined on integers rather than just the natural numbers, but negative factors aren't interesting, they're just the same as the positive ones but with a minus sign.]

Let's look at the two definitions:

1) From this definition, for zero to be a factor of zero, zero would have to divide zero with no remainder. What is zero divided by zero? That's my all-time favourite maths debate (and you all know I love to maths debate). Here are three possible answers:

-Anything divided by zero is infinity, therefore the answer is infinity.
-Zero divided by anything is zero, therefore the answer is zero.
-Anything divided by itself is one, therefore the answer is one.

In fact the answer could be anything you want it to be:
0 x pi = 0
Therefore 0/0 = pi.

So we say the question (and therefore the answer) is undefined. Or "MA ERROR" on your old Casio.

So by this definition, zero is not a factor of zero, in fact it can't be a factor of anything. However, every other number must be a factor of zero. Zero divided by anything other than zero is zero, which is a whole number with no remainder.

2) I think we'd all agree there exists a p such that 0 x p = 0. There are infinitely many such p! So by this definition, zero is a factor of zero.

So what is the answer? Well I'm going to solve this mathematical mystery the way mathematicians solve most of the really puzzling mathematical mysteries. I'm going to use the magic words: "by convention".

By convention, zero is not a factor of itself.

Done.

Emma x x x

The Terrible Twos

This week marks my two year anniversary as a qualified teacher, and also the two year anniversary of NQTpi. Woo!

As a third-year teacher, I look forward to:
-A slight pay rise (the last automatic one I'll have. Cheers for that, government).
-The authority that comes with the phrase "I used to teach your brother" (of course this is far less impressive than "I used to teach your father", but I've got a good few years until that one I hope).
-Possibly having a TLR (teaching and learning responsibility). I am interviewing for this next week.

Now that the "terrible twos" are behind me and I enter my third year, I thought I'd talk about the terrible twos that appear in mathematics. That is, the things in maths that are always taught together, but perhaps shouldn't be.

Word association test (please join in at home):

Area and ...

HCF and ...

Differentiation and ...

Volume and....

Here's what I think you said: perimeter, LCM, integration, and surface area. Am I right? If you didn't, then I'm guessing you're not a maths teacher.

These things are always taught in pairs. And these are all things that get confused.

My year 9 class are not completely stupid. But every single time they are asked to find the area of a shape, most of them give me the perimeter instead. Why?! I think it is fairly obvious that the word "area" means the amount of space inside the shape. I don't see how this can be confused with the length of the border. But students always get these confused.

Area and perimeter are always taught at the same time. I have heard many maths teachers say that they shouldn't be. They are two entirely different concepts, after all. If we taught them separately, would this confusion be avoided?

Similarly with HCF and LCM. My top-set students always get these confused. I think it's because they think that the HCF must be higher than the LCM, because of the name.

For me, the really interesting one is integration and differentiation. Obviously these are opposites. They're inverse operations, according to the Fundamental Theorem of Calculus. But when you think about what they actually do, they don't seem to be that linked at all. Finding the gradient and finding the area don't seem that similar. I think what many maths teachers do is teach differenriation, then teach un-differentiation, and announce that this is called integration, and then teach the application of integration to finding areas. I believe it should be the other way round: teach integration in its own right, and then discover that, holy sh*t, it's the opposite of differentiating! By the way, if your students swear in maths lessons it's a sign that you're doing something right.

Where do you stand on the area/perimeter: together or apart debate?

And congrats to all PGCE/GTP/PGDE teachers that have just qualified! Enjoy your NQT year!
And also congrats to all NQTs who have just passed their probation year! Enjoy your terrible twos!

Emma x x x