Classic Mistake Podcasts and Posters

How on earth can posters of mistakes help with teaching maths?
The full series of Classic Mistake posters have been on display in the Maths classrooms and corridors of my school since 1997. At the time, some staff had concerns about them "sending out the wrong message" by showcasing incorrect maths, but such worries have proven unfounded.

In fact, the whole concept appears to have been embraced by everyone and students often joke with one another about avoiding "the Classics". It's okay to make these mistakes once, but they shouldn't keep making them. Awarding them a "I made a Classic Mistake today" sticker also helps to reinforce in their minds each of these avoidable errors (see the 'Freebies' tab to download these stickers).

And how many posters do you currently have up in your classroom that actually require the reader to think about what they are looking at? Many a visitor to my classroom has either been intrigued to find out what was wrong with the poster they were looking at, or they have taken great pride in having spotted what was wrong with it.

On a more anecdotal level, there has been a school five-a-side football team who called themselves "Classic Mistake Number 5", some of our students leaving for University asked for their own copies of the posters, and in 2006 the Sixth Form Revue even contained a short movie sketch whose punchline included the phrase "Classic Mistake Number 1". Proof of the impact that they could also make in your school?


What are Classic Mistakes?
A mistake in Maths earns "Classic Mistake" status if it is regularly made year in, year out, by successive classes of pupils or students, in classrooms.
They even get to the point where teachers will often incorporate Classic Mistakes into their lessons as teaching points.
If the students know where the pitfalls are, then they have a better chance of avoiding them - well, that’s the theory at least!

Where have they come from?
Mainly from marking exam scripts, and observing which errors were most prevalent.
Some have been suggested by students.
Others have arisen from sheer teacher frustration!

What’s the Gallery all about?
In the Gallery you can see at a glance each of the Classic Mistake posters and download a single copy of either a colour or black and white poster.
Also you can listen to the mp3 audio file that accompanies it, or download it for listening to later.

What are the mp3 files?
They are mainly the verbal explanations that might be given to students who can’t spot what the mistake in each poster is.
They are presented here in the style similar to many podcasts that are already available on the Internet - bit of music, bit of chat and ending with a bit of music.
The 41 audio files that accompany the original 41 posters were created over a period of 8 months, from November 2006 to July 2007. That's an average of one every 6 days!
If you're a teacher, why not use the posters and audio files in your lessons - it's one way of changing the pace of revision lessons.

Wow, there’s tonnes of stuff here!
Yes there is.
There are currently over 170 posters on this website that you can download, print off and decorate your maths classroom, maths corridor or whole school with!
Encourage your students to visit the website, check out if they can spot the mistakes in each poster, listening to the mp3 commentary if they can’t.

How did you create this website, and all the stuff on it?
All the posters were created in Microsoft Publisher and converted to pdf format using Adobe Acrobat.
The .mp3 audio files were created using Audacity via Sennheiser PC155 headphones with microphone.
The sound effects used in the podcasts were found here and here whilst links to the music artists' websites are on my Podcasts tab.
I've also recently been notified of a great new website for even more sound effects, at Sound Snap.
Various websites were trawled to find the javascripts required to make this website work the way it does.
A Quicktime Player Plugin detector in javascript came from here.
The pop-up window that displays large images whilst also playing the mp3 came from here.
A tutorial on how to use Cascading Style Sheets was found here.
Helpful websites about creating podcast feeds were here and here.

Who are you?
My name is Nevil Hopley and I am currently Head of Maths at a large independent school in Edinburgh, Scotland.
I've been teaching Maths in classrooms since 1993, creating websites since 2003 and maths podcasting since 2006.

Who plays the background music?
There are various artists' work featured in these podcasts.
Listed below, in order of their featured Classic Mistake number, are the ones used
1. "Old Man Kulu" by Gecko 3, a local Edinburgh band.
2. "Answers" by Debz, a school band recorded in June 2006.
3. "Living in the Family" by The Xtras, a local Edinburgh band.
4. "Face the Facts" by Bergin, a school band recorded in June 2006.
5. "Answers" by Debz, a school band recorded in June 2006.
6. "Living in the Family" by The Xtras, a local Edinburgh band.
7. "Old Man Kulu" by Gecko 3, a local Edinburgh band.
8. "Answers" by Debz, a school band recorded in June 2006.
9. "Living in the Family" by The Xtras, a local Edinburgh band.
10. "Face the Facts" by Bergin, a school band recorded in June 2006.
11. "Answers" by Debz, a school band recorded in June 2006.
12. "Bombers" by The Sharp Things, used under the Creative Commons Licence.
13. "Had a Plan, Had to Change it" by Derek K Miller, used under the Creative Commons Licence.
14. "Meltdown Man" by Derek K Miller, used under the Creative Commons Licence.
15. "Cold Cloth and an Ice Pack " by Derek K Miller, used under the Creative Commons Licence.
16. "Hotcake Syrup" by Derek K Miller, used under the Creative Commons Licence.
17. "Living in the Family" by The Xtras, a local Edinburgh band.
18. "Face the Facts" by Bergin, a school band recorded in June 2006.
19. "Answers" by Debz, a school band recorded in June 2006.
20. "Bombers" by The Sharp Things, used under the Creative Commons Licence.
21. "Had a Plan, Had to Change it" by Derek K Miller, used under the Creative Commons Licence.
22. "Meltdown Man" by Derek K Miller, used under the Creative Commons Licence.
23. "Cold Cloth and an Ice Pack " by Derek K Miller, used under the Creative Commons Licence.
24. "Hotcake Syrup" by Derek K Miller, used under the Creative Commons Licence.
25. "Living in the Family" by The Xtras, a local Edinburgh band.
26. "Face the Facts" by Bergin, a school band recorded in June 2006.
27. "Answers" by Debz, a school band recorded in June 2006.
28. "Bombers" by The Sharp Things, used under the Creative Commons Licence.
29. "Had a Plan, Had to Change it" by Derek K Miller, used under the Creative Commons Licence.
30. "Meltdown Man" by Derek K Miller, used under the Creative Commons Licence.
31. "Cold Cloth and an Ice Pack " by Derek K Miller, used under the Creative Commons Licence.
32. "Hotcake Syrup" by Derek K Miller, used under the Creative Commons Licence.
33. "Living in the Family" by The Xtras, a local Edinburgh band.
34. "Face the Facts" by Bergin, a school band recorded in June 2006.
35. "Answers" by Debz, a school band recorded in June 2006.
36. "Bombers" by The Sharp Things, used under the Creative Commons Licence.
37. "Had a Plan, Had to Change it" by Derek K Miller, used under the Creative Commons Licence.
38. "Meltdown Man" by Derek K Miller, used under the Creative Commons Licence.
39. "Cold Cloth and an Ice Pack " by Derek K Miller, used under the Creative Commons Licence.
40. "Hotcake Syrup" by Derek K Miller, used under the Creative Commons Licence.
41. "Living in the Family" by The Xtras, a local Edinburgh band.
42. "Face the Facts" by Bergin, a school band recorded in June 2006.
43. "Answers" by Debz, a school band recorded in June 2006.
44. "Bombers" by The Sharp Things, used under the Creative Commons Licence.
45. "Had a Plan, Had to Change it" by Derek K Miller, used under the Creative Commons Licence.
46. "Meltdown Man" by Derek K Miller, used under the Creative Commons Licence.
47. "Cold Cloth and an Ice Pack " by Derek K Miller, used under the Creative Commons Licence.

Here's what's been said about the Posters and Podcasts...

I have just stuck your 'Classic Mistake' posters up in our corridor. They have created fantastic interest amongst our students of all ages and abilities.
Thank you very much!
Ian Classey, Maths Teacher, Istanbul International Community School, Turkey.

Your posters are excellent - after 3 days of printing one out and putting it up for display I have my pupils asking where the next one is! At least I have another 40 days to keep them satisfied!
Dr J Tebbutt, Maths Teacher, Chatham House Grammar, Ramsgate, UK.

Thanks for e-mail, I have just been on your web-site and downloaded posters. I appreciate that you are giving away quality material for free. I hope one day that I can repay in kind. It is refreshing that people are willing to share resources, so that we are not all reinventing the wheel.
Alastair Mills, Maths Teacher, Brechin High School, UK.

Brilliant, I love the "And it's a classic mistake". Standard flop, haha I love it.
James, school pupil of George Watson's College, Scotland, UK.

In the first month of this website going live, there were over 1750 visitors and between them they downloaded over 12400 poster files - that's a mean of 7 files each!

I have forwarded [your website address] on to the NRICH email newsletter groups as you requested - it looks a very worthwhile resource.
Liz Pumfrey, NRICH, University of Cambridge Centre for Mathematical Sciences.

Thank you so much for alerting me to the presence of such a fantastic website - you have brightened up an otherwise boring day in the reading room. I have just listened to your explanation of classic mistake number 2 (a particular favourite!)
Louisa, ex-school pupil of George Watson's College, Scotland, UK.

We enjoyed the podcasts and they are certainly of value to young people, teachers and other educational professionals. We are delighted to include your RSS feed in our directory to help promote the work you are doing - especially as there are few good quality podcasts on mathematics.
Podcast Team at RECAP Limited.

These look great! I'm going to pass them along to my math teacher friends, as well.
Jason Margolis, presenter of The World in Technology Podcast, BBC.

Great posters by the way - I am going to print some off ASAP.
'rustybug', from TES Teaching Ideas & Resources Staffroom Discussion Forum.

Excellent - the maths facts ones are really good as well. Thanks very much - you saved me hours of work.
'emilyisobel', from TES Teaching Ideas & Resources Staffroom Discussion Forum.

Thanks for the tip, looks like some great stuff.
'DiscoStu2005', from TES Teaching Ideas & Resources Staffroom Discussion Forum.

I've sent the link to our maths co-ordinator, thanks.
'MiniOwner', from TES Teaching Ideas & Resources Staffroom Discussion Forum.

These are excellent oscars. Think I'll play some of those mp3 files to my students.
'Casy', from TES Teaching Ideas & Resources Staffroom Discussion Forum.

These are GREAT. THANX
'sunnie_daze', from TES Teaching Ideas & Resources Staffroom Discussion Forum.

Just marked a year 10 test this week and have printed out four of the classic mistakes posters already.
'mmmmmaths', from TES Teaching Ideas & Resources Staffroom Discussion Forum.

These look excellent (and yes they are classics!)
Damian Rogan, Maths Teacher, Havering Sixth Form College, UK.

Hi, I think your classic mistakes posters are great. Have just printed them to SMART Notebook so I can display them on the SMARTBoard to talk about them with Year 11 in revision time. [To download this Notebook file, or click here]
The website is fantastic - only just discovered it but there is loads that I will use - many thanks
Liz Wallace, Maths Teacher, Fallibroome High School, UK.

Now we have all 41 classic mistakes displayed at the front of the class, my boys are asking for more ... Fortunately the Year 12 Further Maths class have started to suggest and design their own! Thanks for providing such a stimulating discussion through the posters, that will doubtless continue for many months yet.
Dr John Tebbutt, Maths Teacher, Chatham House Grammar School, Ramsgate, Kent, UK

I think these are great. I have an idea to print and laminate them A5 and have them to use like a referee has yellow and red cards
'daveph', from NCETM Recommend a Resource Discussion Forum.

A selection of the Posters have been displayed in all Maths Classrooms and has provoked some discussion from students who should have been listening to me! Excellent
'MarkGreenaway', from TES Resource Bank Pages.

Some of those are great - I can see a lesson idea forming now - getting students to correct each classic mistake - or how would they explain why it is a mistake - or even have some statements that are correct and have the students sort them and make their own posters.
'MathsHOD' , from TES Mathematics Staffroom

I have these laminated and all over my classroom. I keep meaning to use them as plenaries, but haven't as yet. Maybe now is the time.
'emilyisobel', from TES Mathematics Staffroom

These are laminated and displayed all over our corridor. The whole series is there.
'rustybug', from TES Mathematics Staffroom

Yup, all laminated and all round my room as well (thanks to one of you who mentioned them before). Pupils love them and it prompts lots of discussion...
'hardlife', from TES Mathematics Staffroom

We have just started podcasting and have a few episodes up now. I was just browsing around for other maths podcasts, found yours and think it's great!
We're going to do some plugging of other maths podcasts in our newsletter rather soon so we'll certainly give it a mention.
Marc West, editor of "Plus" - an online Maths magazine, UK.

I love the posters. What is going on with the decimal point though? You show 3.1 with the decimal point in midair looking like a multiplication operator. Is this a UK thing or a formatting issue?
Ellen Hansen, by email.
My reply: In the UK we'd write 3x4x5 in shorthand exactly as "3.4.5" Hence a full stop does mean multiplication. The "midair" dot is a decimal point in the UK, not a multiplication sign. So things are the opposite way round from how it's done in the USA, for example.

I think it's great you post the "mistakes" page because it really gets us thinking about how students learn and why they make the errors they do!! Keep it up
Mark, from Homeschool Math Blog.

These posters make it cool to be a math geek, and fun to be corrected! I think I'd like to start a Classic Grammar Mistakes list, beginning with, "We have car's for sale."
'cm', a home educated student in the USA.

I really enjoyed the posters....great ideas for getting my math students to write about math. We have to do some of the Collins Writings, so these are some good ideas!
Anonymous, from Homeschool Math Blog.

I love the classic mistakes posters. I find that the students read them, identify with them, take comfort in the fact that they're not the 'only' one to have got it wrong.
They get students talking about maths - which is what a display is for - isn't it?
'suef11', from TES Mathematics Staffroom

I have several of these posters on display and have found they promote excellent discussion. Many students are keen to understand the mistake and make sure that they don't make the same ones.
I hope that an awareness of the classic mistakes means students will make them less.
'Casy', from TES Mathematics Staffroom

I also really like the "Real Maths Problems" also available on that site... Whilst not of great mathematical content they do make me laugh!
'andykemp', from TES Mathematics Staffroom

Excellent site
'LadsNR', from TES Mathematics Staffroom

I'm an NQT just going into my third term in a Year 6 class and I just had to say thank you very much for all the work you have put into these and for making them free! Although I can not use everything on here there is certainly loads of it that I can, especially with SATs coming up. You have just saved me hours in thinking up a display!
Eleanor Prescott, NQT, Hampshire

I am compelled to write to say what a great idea this is! Can't wait to try these out with my GCSE classes this coming year.
Ruth Christopher, Maths Teacher, Cramlington Learning Village, UK.


Printing Troubleshooting
When printing pdf files of posters to certain printers, some problems have been found to occur.
One remedy is to locate any "Advanced Printing" options and select "Print as Image" if you can.
Also, do not have your pdf viewing software reduce the image to fit printer margins - there is already sufficient blank space around the edges for this not to be a concern.

Classic Mistake Posters
Download all Posters in Colour [4.6Mb]
Download all Posters in Black & White [6.2Mb]
 Download the first 41 Posters as SMARTBoard Notebook [1.6Mb]
You can download the full collection of posters using the above links, or you can download individual posters from the Gallery. Both Colour and Black and White versions are available.
One way to use them is to print them off A4 size, enlarge photocopy to A3 coloured card, laminate and then display them on walls. If you can colour print to A3 coloured paper or card, then that is even better.
Have your students try and find the mistake in each poster - a great form of pre-exam revision!
   
Classic Mistake Stickers
Download Stickers [1.8Mb]
A Mistake’s not worth making unless you gain recognition for it!
Why not download this pdf file, acquire some sheets of labels for your printer (either 21 or 24 to a sheet) and have them available in class to give to students who make the mistakes. Some of the pages in the pdf file can generate 42 or 48 stickers per sheet of 21/24 stickers, by cutting the sheet along the lines shown.
You’ll be surprised how much pleasure students get from receiving one of these stickers.
Be careful not to encourage them to make mistakes though….!
   

Classic Mistake Instruction Poster
Download Poster [240Kb]
Pop this poster up on the wall next to all the others, just to make sure your readers know what to do!
The pdf file contains both a black and white, and colour copy of this poster.

 
   

Classic Mistake Website Advertising Poster
Download Poster [209Kb]
Download this poster to adorn your classroom and corridor walls to direct students to log onto the website and hear the podcasts for themselves.
Suggestion: print off A4 size, chop and trim to get two posters from each A4 sheet, laminate and display.
   
Maths Facts Posters
Download Posters [2.5Mb]
Download Posters as SMARTBoard Notebook [1.1Mb]
These 59 posters form a collection of facts that students of Mathematics just need to know.
Suggestion: print off A4 size, enlarge photocopy to A3 coloured card, laminate and display.
Why not change them around every week and see if students notice?!
Why not play the game of show 10 of them to a class, change one when they are looking away, and then see if they can name which one has been changed.
   
The REAL Maths Problems Posters
Download Posters [1.8Mb]
These 23 posters form a collection of tongue-in-cheek posters, designed to be displayed at a jaunty angle. Each poster starts off in the same style as a typical question from a maths textbook or exam paper. However, instead of the traditional ending question, these offer an alternative issue to consider.
Suggestion: print off A4 size, photocopy to A4 coloured card, laminate and display.
Warning: not everyone understands these at first reading ... but that’s often the best bit!
   

Random Dot Stereogram Posters
Download Posters [230Kb]
These 5 posters are based upon the same principal as the "Magic Eye" posters that have been around for many years. The images were generated on a TI-92 graphic calculator.
Stare at them long enough and you’ll claim to see anything!
Suggestion: print off A4 size, enlarge photocopy to A3 card, laminate and display. It’s not known whether copying them to coloured card makes them any easier to see!
   
Pictures of Prime Numbers Posters
Download Poster [40Kb]
A single colour poster that shows all the prime numbers up to about 8500 in an innovate way that reveals some hidden patterns in their regularity.
Suggestion: print off A3 size in colour, laminate and display.
   

Investigations Checklist Poster
Download Poster [40Kb]
If you do any form of investigative work as part of your course, then this poster can remind students of the key steps to ensuring that they can make good progress through the "pattern spotting" phase of their work.
Suggestion: print off A4 size, enlarge photocopy to A3 coloured card, laminate and display.

 
 
Teachers Open The Door...
Download Poster [49Kb]
A single colour poster that promotes students being proactive about furthering their knowledge.
Suggestion: print off A3 size in colour, laminate and display.
   
I Don't Want The Answer, I Want the Solution
Download Poster [16Kb]
A single colour poster that reinforces that as Maths teachers we are rarely interested in the final answer, but more interested in the solution process that was followed to obtain it.
Suggestion: print off A3 size in colour, laminate and display.
   

Maths is Like Skateboarding
Download Poster [85Kb]
A single colour poster that reminds students that a bit of perseverence is required to really master something (and not just Skateboarding!)
Suggestion: print off A3 size in colour, laminate and display.
   
Mathematical Scaffolding
Download Poster [146Kb]
Two colour posters that complement each other. The idea behind them is that if all the ladders were already in place on the scaffolding, this is akin to 'spoonfeeding' students. It's much more fun (and beenficial) for them to make their own way through a problem, designing their own route.
Suggestion: print off each on A3 size in colour, laminate and display.
The Illiterate of the 21st Century
Download Poster [68Kb]
A single colour poster that puts an image to a famous quote, and that reminds Maths students that the only way to do something is not always the first one that they met.
Suggestion: print off A3 size in colour, laminate and display.
   

Make The Finding Yourself
Download Poster [55Kb]
A single colour poster that goes well with the Scaffolding posters, above.
Suggestion: print off A3 size in colour, laminate and display.
   

HSBC Maths
Download Poster [99Kb]
A single colour poster that was inspired by the HSBC posters that were on display in and around 2010. This is a poster for teachers as much as students!
Suggestion: print off A3 size in colour, laminate and display.