bodmas blog

Microsoft’s Raymond Chen tells the story of a customer who complains that the keyboard isn’t working. Of course, it’s unplugged. If you try asking them if it’s plugged in, “they will get all insulted and say indignantly, ‘Of course it is! Do I look like an idiot?’ without actually checking.”

“Instead,” Chen suggests, “say ‘Okay, sometimes the connection gets a little dusty and the connection gets weak. Could you unplug the connector, blow into it to get the dust out, then plug it back in?’

“They will then crawl under the desk, find that they forgot to plug it in (or plugged it into the wrong port), blow out the dust, plug it in, and reply, ‘Um, yeah, that fixed it, thanks.’”

Quoted from Seven Steps to remarkable customer service by Joel Spolsky, found via Seth Godin’s blog. Teaching basic maths to adults can involve a certain amount of ‘blowing off the dust’. I’m finding that emphasising the learning process (forming schema, working memory and so on) helps students talk about learning blocks on basic material. More on this when I have worked up the material with some examples.

I have taken to putting a small version of the table below in the top right of my PowerPoint slides and as an A3 poster on the (ink powered) whiteboards I use in many teaching rooms.

Students at level 2 doing algebra need to use these facts in most lessons, and seeing the rules all in one place seems to help.

I feel a YouTube coming on once I shift this cold…

A pair of directed numbers….	Adding and subtracting	Multiplying and dividing
Same signs	Add the numbers The sign of the answer is the same as the sign of the numbers	The answer will be positive
Opposite signs	Find the difference of the numbers The sign of the answer is the same as the sign of the largest number	The answer will be negative

“But is it better for the teacher to present the material already grouped? How does that follow? If the intent is to have the student learn the information (ugh, bad terminology) then we must ask, is it the groups that aide remembering and understanding, or the process of grouping that does this? If it’s the latter, then presenting the information already grouped may help the teacher remember, but will do nothing for the student.”

Stephen Downes responding to a post by Clive Shepherd about how neuroscience may or may not help the teacher.

Clive Shepherd was posting some interesting notes from a presentation given by Dr Itiel Dror of Southampton University. The presentation was about how neuroscience may inform the design of e-learning materials and experiences, although I think the points being made could apply to the classroom as well.

Most of my teaching now is about process; how to solve mathematical problems, how to design experiments, how to write about science, so I think I am with Downes on this one.

• Clive Shepherd’s original post
• Downes response
• Itiel Dror’s Southhampton University home page

The BBC provide MP3 files of a few radio programs, including Melvyn Bragg’s In Our Time history talks. I often pop the MP3s onto a player and listen to them on the train.

This week’s issue is what Mr Bragg refers to as an ‘authored piece’ with interviews on location in Hull, Westminster Abbey and Clapham. Sounded good, but…

So, as I will be working on both repeats, I either listen again over the broadband connection or I skip the program. I’m a little hazy as to how being able to download an MP3 poses a bigger copyright risk or profile than the ‘listen again’ facility. Streaming audio can be recorded and converted in a few mouse clicks, hardly a huge barrier. The fact that it is a documentary about the abolishion of slavery I can’t download adds a mild irony to the situation.

Rebecca Newburn has provided a page about PEDMAS, and she is using Seth Godin’s Squidoo to publish the information – an interesting choice. The page leads to some handy YouTube tutorials, and has links to games and other interactive content.

In the UK, we use BODMAS or BEDMAS as a mnemonic acronym(!) to remember the order of operations;

Brackets
Of (or Exponential)
Divide
Multiply
Add
Subtract

In the US, they use PEDMAS, the P for parenthesis. That is probably the reason I was able to register the bodmas domain.

Rebecca’s home page has links to more YouTube tutorials. I look forward to when I can provide (say) 10 YouTubes covering common topics but then find 50 others that I can use in return and then cover a whole Maths unit. Those students who appreciate interactive online material might engage more, and those who prefer the printed page and a teacher to answer questions can still feel fully supported.

Nice to see ‘vedic maths’ (digit sums and partial products) being used as an alternative for US kids to try; many of my Sikh and Hindu students are experts and can extract roots of 8 digit numbers in their heads. It is surprising how many people can remember the Trachtenberg Speed System of Arithmetic – this was used widely in banking and insurance in the UK up until the 1970s.

Food for thought : the sohcahtoa domains in the UK are still mostly available. sohcahtoa.org is registered to someone in Berkley (makes sense) but, alas, is not yet being used.

OpenOffice 2.2 works same way :: except that I had to run the dpkg command using sudo, and there were a few more error messages about scripts. Installed on a fresh Xubuntu 6.06.1 install.

Summary: you can use the tutorials from various sources for installing the most recent OpenOffice 2.1 on Ubuntu with a fresh Xubuntu install. My earlier problems with dependencies were caused by me not realising that you must convert the OpenOffice RPMs on the machine you are installing on.

Overview

You can install the version of OpenOffice available in the repositories for Dapper easily from Synaptic, however you are then stuck with an early development release of OpenOffice 2 (around 2.02 or 2.03). The instructions on this page record how I was able to install the most recent OpenOffice 2.1.0 version on the laptop into a fresh install of Xubuntu.

The binary build of OpenOffice 2.1 for Linux is distributed as a series of RPM packages. Xubuntu is a Debian based system and needs .deb packages. There is a program called ‘alien’ that will convert RPMs to .debs, but the conversion needs to be done on the computer you intend to install OpenOffice onto! My earlier difficulties resulted from transferring the .debs built by alien on my little Dell laptop to the P4 desktop – bad move.

The following steps are needed

1. Update and upgrade
2. Install Alien
3. Download OpenOffice Linux
4. Unpack the archive
5. Convert the RPMs into .debs using Alien
6. Use dpkg to install OpenOffice from the generated .debs

Update and Upgrade

No extra repositories need be enabled in Xubuntu. To update and upgrade your installation start a terminal session and type.

sudo aptitude update && sudo aptitude upgrade

If you use Synaptic to do automatic updates, you probably don’t need this step. At the time of writing (Feb 2007) I needed to download 90Mb of packages to upgrade a fresh install of Xubuntu 6.06.1 Dapper.

Install Alien

Alien is available in the Ubuntu repositories and can be installed using the command

sudo aptitude install alien

On a fresh Xubuntu install, Alien pulled down about 40Mb of packages. I should have realised that alien does rather more than just convert a compressed file from one form to another. This is why it is important to do the conversion on the computer you intend to install OpenOffice on.

Download OpenOffice version 2.1

Download the linux version of OpenOffice from the OpenOffice download page. This is a 120Mb+ of gzipped archive, and so might take some time. I noticed that the download speed was around 48 to 64Kb/s which is well below the speed of my DSL connection.

Unpacking and converting

The commands below will unpack the OpenOffice binaries into a folder with a long name on your desktop, and then change working directory into the folder within the OOE… folder that contains the RPM files for conversion. I use the * character as a wild card to avoid having to type the full folder name.

cd Desktop
tar zxvf OOo_2.1.0_LinuxIntel_install_en-US.tar.gz
cd Desktop/OOE*/RPMS

The conversion command is simply

alien --keep-version *.rpm

By default, alien creates .deb files with a version number one higher than the .rpm files. The—keep-version option prevents this; I am trying to allow for future upgrades without confusion caused by version number change. The conversion process took around 18 minutes on the 700MHz laptop, and about 7 or 10 minutes on the P4.

Once the conversion is complete, I deleted the kde-integration and gnome-integration debs using Thunar. These files may have caused some of the problems I had in my first attempt at installing OpenOffice!

Installing using dpkg

Finally, installing OpenOffice takes about a minute! Just issue the following command from the terminal in the RPMS directory

dpkg -i *.deb

You will see an error message about the OpenOffice core-10 package not being able to run scripts, ignore this, I have not seen any problems as a consequence.

Then change directory to the desktop-integration sub directory and run the debian desktop integration package;

cd desktop*
dpkg -i *.deb

All should now be installed. Right click over the desktop and select the Office menu; you should see all the OpenOffice components.

This is the kind of production that might involve and intice the elusive 19 to 25 year old market. This engaging video works at the emotional level (c.f. Seth Godin’s Really Bad PowerPoint) but also manages to impart some information.

• Digital Ethnography blog