The PoSWW below is courtesy of Glen Wheeler (who is trying to distract us from another university). It comes from Macquarie University’s new ad campaign.

# Tag: indices

## PoSWW 7: Power Outage

## Signs of the Times

Our second sabbatical post concerns, well, the reader can decide what it concerns.

Last year, diagnostic quizzes were given to a large class of first year mathematics students at a Victorian tertiary institution. The majority of these students had completed Specialist Mathematics or an equivalent. On average, these would not have been the top Specialist students, nor would they have been the weakest. The results of these quizzes were, let’s say, interesting.

It was notable, for example, that around 2/5 of these students failed to simplify the likes of 81^{-3/4}. And, around 2/3 of the students failed to solve an inequality such as 2 + 4x ≥ x^{2} + 5. And, around 3/5 of the students failed to correctly evaluate or similar. There were many such notable outcomes.

Most striking for us, however, were questions concerning lists of numbers, such as those displayed above. Students were asked to write the listed numbers in ascending order. And, though a majority of the students answered correctly, about 1/4 of the students did not.

What, then, does it tell us if a quarter of post-Specialist students cannot order a list of common numbers? Is this acceptable? If not, what or whom are we to blame? Will the outcome of the current VCAA review improve things, or will it make matters worse?

Tricky, tricky questions.

## What is this Crap Here?

OK, Dear Reader, you’ve got work to do.

So far on this blog we haven’t attacked textbooks much at all. That’s because Australian maths texts are, in the main, well-written and mathematically sound.

Yep, just kidding. Of course the texts are pretty much universally and uniformly awful. Choosing a random page from almost any text, one is pretty much guaranteed to find something ranging from annoying to excruciating. But, the very extent of the awfulness makes it difficult and time-consuming and tiring to grasp and to critique any one specific piece of the awful puzzle.

The Evil Mathologer, however, has come up with a very good idea: just post a screenshot of a particularly awful piece of text, and leave others to think and to write about it. So, here we go.

Our first WitCH sample, below, comes courtesy of the Evil Mathologer and is from Cambridge Essentials, Year 9 (2018). You, Dear Reader, are free to simply admire the awfulness. You may, however, go further, and what you might do depends upon who you are:

- If you believe you can pinpoint the awfulness in the excerpt then feel free to spell it out in the comments, in small or great detail. You could also offer suggestions on how the ideas could have been presented correctly and coherently. You are also free to ponder how this nonsense came to be, what a teacher or student should do if they have to deal with this nonsense, whether we can stop such nonsense,* and so on.
- If you don’t know or, worse, don’t believe the excerpt below is awful then you should quickly find someone to explain to you why it is.

Here it is. Enjoy. (**Updated below.**)

* We can’t.

## Update

Following on from the comments, here is a summary of the issues with the page above. We also hope to post generally on index laws in the near future.

- The major crime is that the initial proof is ass-backwards. 9
^{1/2}= √9 by definition, and that’s it. It is then a consequence of such definitions that the index laws continue to hold for fractional indices. - Beginning with 9
^{1/2}is pedagogically weird, since it simplifies to 3, clouding the issue. - The phrasing “∛5 is irrational and [sic] cannot be expressed as a fraction” is off-key.
- The expression “with no repeated pattern” is vague and confusing.
- The term “surd” is common but is close to meaningless.
- Exploring irrationality with a calculator is non-sensical and derails meaningful exploration.
- Overall, the page is long, cluttered and clumsy (and wrong). It is a pretty safe bet that few teachers and fewer students ever attempt to read it.