The following comes courtesy of frequent commenter, John Friend. It is an exercise and solution from *Cambridge Specialist Mathematics 3&4*.

# Category: WitCH

## WitCH 62: Video Killed the Proficiency Star

It’s not fun, but we gotta do it.

Yesterday, we wrote about Ofsted’s review of mathematics education. We wrote that it is a great review, and it is a great review. It is perfect in its reactionaryism. But, alas, there’s also a video.

Below is Hannah Stoten, one of the review authors and future kidnap victim, launching the review. An excellent review, and a well-spoken author. What could go wrong?

**UPDATE (01/06/21)**

Well, that’s not good:

Nonetheless, we’re willing to assume that Hannah is innocent here, and plans to kidnap her and bring her to Australia are proceeding apace.

## WitCH 61: Wheel of Misfortune

We decided ACARA’s psychedelic circle, which we discussed briefly here, was worthy of its own post. So, apart from the potential to trigger an epileptic fit, what is wrong with ACARA’s wheel?

ACARA labels their wheel as depicting

*[the] relationship between the six strands and three core concept organisers*

The six strands make up the inner wheel, and are explained here (pages 4-5). The three “core concept organisers” are the three colours on the wheel rim, with the categories and subcategories as pictured below, and which are explained here (pages 5-8).

## Being Carvalho With the Truth

There are bigger, stupider fish to fry, but this also needs to be done, and it’s now or never.

Earlier this week, David de Carvalho, the CEO of ACARA, gave a speech at The Age Schools Summit. flagging the Daft Australian Mathematics Curriculum (the spelling is correct). Our most recent WitCH is based on an excerpt of de Carvalho’s speech, but the entire speech — also condensed to an op-ed — is worthy of scrutiny. And so, here we are.

Below are parts of de Carvalho’s speech that relate in some manner to the mathematics review, followed by our, mostly redundant, comments. What de Carvalho says is clear, and clearly ridiculous.

*The data that we get from NAPLAN is important, but it is not a measure of overall school quality, and we need to remember that education is a complex multi-dimensional process where improvement does not rely on the rationalistic analysis of data and the application of associated managerial techniques.*

“Rationalistic” is now a boogie-man word? That’s where we are? And once again, we have this idiotic selection: NAPLAN or touchy-feely. A pox on them both.

For the thousandth time, NAPLAN is garbage. Numeracy is garbage. And, while we’re at it, PISA is garbage. If there were decent national tests of *arithmetic* and *mathematics*, these would be a godsend; the subsequent “rationalistic analysis” would do more than anything else imaginable to lift Australian mathematics education. But, of course, courtesy of two very poxy houses, there’s not a snowflake’s chance in Hell of this occurring.

*This is because the essential nature of education is that it involves a sense of historic continuity and conversation between generations, between teachers and their students, where a learner is engaged in the process of becoming a well-rounded human being …*

*This conversation between the generations is the basis of the curriculum.*

An A^{+} for irony. If there is one central theme to the now decades of destruction to Australian education, it is an utter contempt for the past, the active denigration and wilful forgetting of Australia’s one-time educational excellence.

*Up to now, we have been working with 18 teacher and curriculum reference groups established to support the review, made up of 360 teachers and curriculum authority representatives from across Australia, as well as consulting with our peak national subject bodies and key academics. I’ve also had discussions with the staff from 24 primary schools across the country.*

That’s a lot of people. What could go wrong?

*But on Thursday, we begin public consultations on the proposed revisions to the Foundation to Year 10 Australian Curriculum.*

No, you aren’t. You are permitting people to fill in a survey, which, presumably, will never see the light of day. In no manner does this sham hold ACARA publicly accountable to publicly available opinion.

*I’ve heard some stakeholders say that we should be “taking a chainsaw to the curriculum”, but chainsaws are not particularly subtle, and can leave an awful mess behind.*

What is currently wrong with the Australian Curriculum is also not subtle. We’d go for dynamite, but a chainsaw would do in a pinch.

*We need to avoid perpetuating a false dichotomy between factual knowledge and capabilities such as collaboration and critical thinking.*

Yes, …

*You can’t engage critically and creatively on a topic if you lack the relevant background knowledge …*

Go on, …

*So the ability to recall facts from memory is not necessarily evidence of having genuine understanding.*

A very cute straw man, but please continue.

*A student might, for example, memorise the formula for calculating the length of the hypotenuse if given the length of the other two sides of a right-angle triangle, but do they understand why that formula, known as Pythagoras’ theorem, works every time? The process of discovering that for themselves, with the assistance of the teacher, is what makes learning exciting. And it’s what make teaching exciting. Seeing the look of excitement on the face of the student when they experience that “aha!” moment.*

Ah, so *that’s *what you’re getting at. You nitwit.

This example is so monumentally, multidimensionally stupid, it has its own post.

*Some learning areas have only required some tidying – but others have required more focus. Maths for example has required greater improvement and updating.*

If we look at our PISA and our TIMSS results, Australian students are not bad at knowing the “what”, but we are not as strong at “why” of mathematics, …

This is, to use the technical term, a fucking lie. It is an absurd, almost meaningless dichotomy. And you forgot the “how”, you idiot. But in any case Australian students absolutely suck at the “what”, and the “how”, and ACARA damn well knows it.

This is THE lie. This pretence, that Australian maths students are doing just fine on the basic knowledge and skills, is why it is absolutely impossible for ACARA to revise the mathematics curriculum in a meaningful manner. This is why, without even needing to read it, you *know* the Draft Curriculum is a farce.

*… this joint statement from five of the leading maths and science organisations in the country is an indication of the level of interest out there about the curriculum.*

Yep, “five of the leading maths and science organisations” can endorse this poisonous twaddle. That’s where we are.

*Again – knowledge and capabilities being acquired together.*

Mate, it doesn’t work that way. More often than not, and particularly in primary school, your precious “capabilities” are just getting in the damn way. You can wish it all you want, but learning mathematics just doesn’t work that way.

*It should be noted that the current Australian Curriculum in Mathematics already includes four Proficiency Strands: understanding, fluency, problem-solving and reasoning. The issue has been that these proficiencies have not been incorporated into the Content Descriptions, which is what teachers focus on.*

*So the major change we have made in the proposed revisions to Maths is to make these proficiencies more visible by incorporating them into the Content Descriptions.*

In other words, you are changing the Curriculum *content*, and you are pretending that these changes are simply an innocent act of tidying up. Do you imagine anyone believes you?

*It is also important to note that in proposing these revisions, ACARA is not making any recommendations about pedagogical approaches. *

So that Pythagoras nonsense back there was just for the Hell of it? There’s a technical term for this. What was it again?

I expect we will see a stirring of the passions.

So you’re ok with passions. How do you feel about white-hot fury?

*No doubt some will argue the proposed revisions don’t go far enough, while others will say they go too far, …*

Of course it never crossed your mind that people might say, accurately, that you’re going in entirely the wrong fucking direction.

This discussion and civil debate is a good thing.

It is not a discussion, it is a fait accompli, and there is no benefit here in being civil. What is called for is complete and utter contempt.

## WitCH 60: Pythagorean Construction

Yesterday, David de Carvalho, the CEO of ACARA, gave a speech at The Age Schools Summit. de Carvalho used his speech to set the stage for ACARA’s imminent launch of the draft of the revised Australian Curriculum. (See here.)

We shall take a more careful look at de Carvalho’s speech in the near future. For now, we’ll settle with a WitCH, an excerpt from de Carvalho’s speech:

*“So the ability to recall facts from memory is not necessarily evidence of having genuine understanding. *

*A student might, for example, memorise the formula for calculating the length of the hypotenuse if given the length of the other two sides of a right-angle triangle, but do they understand why that formula, known as Pythagoras’ theorem, works every time? The process of discovering that for themselves, with the assistance of the teacher, is what makes learning exciting. And it’s what make teaching exciting. Seeing the look of excitement on the face of the student when they experience that ‘aha!’ moment.”*

*And when we understand a topic, it is easier to recall the facts because they are no longer just random bits of information but are organised into intelligible ideas. Not only do we know where the dots are, but we know why they are there and how to join them.”*

**UPDATE (29/04/21)**

Just a reminder, this is a WitCH. So, what specifically is crap about de Carvalho’s Pythagoras suggestion?

To guide the discussion, below is (arguably) the simplest, algebra-free proof of Pythagoras, which, undeniably, all students should see. Where does/should this proof fit in with the teaching of Pythagoras, and where does de Carvalho’s suggestion fit in with either of these?

**UPDATE (03/05/21)**

It is extremely helpful of De Carvalho to have selected such a fundamentally flawed example. If he had chosen more judiciously it would be more work to counter, to make the case here against inquiry-based learning. De Carvalho having chosen almost an anti-example, however, makes clear that ACARA’s inquiry push is nothing like a reasoned best-choice approach in given situations, and much more a religious fundamentalism: inquiry is, simply by being inquiry, the preferred method.

De Carvalho contrasts the WHAT of Pythagoras — the equation — with the WHY, the proof (or proof-like evidence for) that equation. Putting aside for the moment De Carvalho’s atrocious suggestion for getting to the WHY, we’ll first note that De Carvalho has failed to ask two fundamental questions:

**HOW**does Pythagoras’s theorem work?**WHY**do we teach Pythagoras’s theorem?^{2}

The first question is about the HOW of the mechanics of dealing with the equation : manipulating for the unknown, taking roots and so on. This HOW is not glamorous, and not intrinsically difficult, but it is fundamental. Of course the application of Pythagoras’s theorem, including the mechanics, is in the draft curriculum (beginning in Year 8), but De Carvalho’s casual airbrushing of the HOW is a tell.

(As a side note, we’re pleased to see that the single stupidest line in the Australian Curriculum is still there, in the Pythagoras elaborations.)

And now, the second question: WHY^{2} teach Pythagoras’s theorem? There are two strong answers to this question, both of which, in different ways, demonstrate that De Carvalho has no understanding of his example.

The first reason, the WHAT to teach Pythagoras is because it is so important: it is the fundamental formula for distance in Cartesian (and Euclidean) geometry.

The second reason, to teach the WHY of Pythagoras’s theorem is because it is a historical icon and because it is so beautiful. The proof illustrated above is gorgeous, it can easily be learned by a primary school student, and it *should* be learned, by *all* students, as one learns a poem. (One can of course extend this to be a third reason, to teach other proofs and the nature of geometric proof.)

Here is why these reasons show De Carvalho’s example to be so empty:

- The two reasons for teaching Pythagoras are almost totally disconnected.
- Hunting for a proof is the absolute worst way to appreciate the beauty of Pythagoras.

Arguing for the WHY, De Carvalho notes,

*And when we understand a topic, it is easier to recall the facts …*

And of course, as a general point, De Carvalho is correct. In regards to Pythagoras, however, De Carvalho is simply wrong. Pythagoras is one of the easiest equations to learn, and students simply don’t need the WHY to know WHAT it is and HOW it works. Secondly, the WHY doesn’t help with the recall whatsoever. Pythagoras is a theorem about *areas*, and its application in school is always to *distances*. The idea that a longer proof about areas will help students recall and understand the use of a simple formula about distances is utterly ridiculous.

As for appreciating the beauty of Pythagoras: if you are given a beautiful poem then you simply teach the poem. It is absurd to think that De Carvalho’s “discovering that for themselves” — which, anyway, will almost certainly be faked — will give students any proper appreciation of Pythagoras. All it can do, and inevitably what it will do, is obscure the simple beauty.

There are zillions of examples of the WHY being critical to understanding the WHAT, and there are even examples where the WHY should replace the WHAT altogether. There are examples where a limited form of inquiry is worthwhile in discovering the WHY and the WHAT. Pythagoras, however, is none of none of these. Pythagoras is only an example of ACARA’s constructivist dogmatism, and of De Carvalho’s ignorance.

## WitCH 59: Stretching the Truth

This double-barrelled WitCH comes from *Maths Quest Mathematical Methods 11* (top). and *Cambridge Mathematical Methods 1 & 2* (bottom). It is the final in our series of Quest-bashing, at least for now.

## WitCH 58: Differently Abled

Like the previous post, this one comes from *Maths Quest Mathematical Methods 11*, and is most definitely a WitCH. It can also been seen as a “contrast and compare” with WitCH 15.

Subsection 13.2.5, below, is on “differentiability”. The earlier part of chapter 13 gives a potted, and not error-free, introduction to limits and continuity, and Chapter 12 covers the “first principles” (limit) computation of polynomial derivatives. We’ve included the relevant “worked example”, and the relevant exercises and answers.

## WitCH 57: Tunnel Vision

The following is just a dumb exercise, and so is probably more of a PoSWW. It seems so lemmingly stupid, however, that it comes around full cycle to be a WitCH. It is an exercise from *Maths Quest Mathematical Methods 11*. The exercise appears in a pre-calculus, CAS-permitted chapter, *Cubic Polynomials*. The suggested answers are (a) , and (b) 81/32 km.

## WitCH 56: Fuzzy Dots

Has it occurred to anyone else that these WitCHes are a blogging Ponzi scheme? As long as we keep posting new WitCHes, no one bugs us about not polishing off the old WitCHes. What the hell; we’ll keep going until someone calls the Blog Cops. And, to continue with the scheme, this WitCH comes from the Cambridge text *Specialist Mathematics 1 & 2*, in the section titled * Linear Diophantine equations.* Happy hunting.

## WitCH 55: Oregonian Dreamin’

It must be something in the water.

This one, with due credit to Bill and Melinda, will be appearing in plenty of right wing snicker-rags in the very near future. It’s really a PoSWW. However, given the previous (and much more important) post, we decided to make it a companion blivit-WitCH. (As well, we’re working on another post on this stuff, in defense of it.)

Courtesy of the Oregon Department of Education, teachers there are being offered a “micro-course” on Equitable Math Instruction. More specific links are below. Good luck, and Good God.

**LINKS **

1. Dismantling Racism in Mathematics Instruction

2. Fostering Deep Understanding

3. Creating Conditions to Thrive (zip file)

4. Connecting Critical Intersections

5. Sustaining Equitable Practice

Whole Course (zip file)