Category Archives: Problem Solving

330. Still Dancing Men

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You may already know about my blog posts on the ‘Dancing Man’ cipher. If not, check them out here;

34. The Dancing Cipher

97. The Dancing Cipher (part two)

Now, I have two parallel classes and I want to set the Dancing Man project as a homework, but they’ll be doing the task at different, but overlapping times. I don’t want the second class to have an unfair advantage, so I’ve written a second task. All the instructions are the same, but it’s a different text. I’m not sure whether to give each class a different text or whether to randomly assign both texts within both classes to avoid copying/generate confusion.

This text is a little more interesting than the last one … think zombies!

You can download an advanced (Beta?) copy below and I’ll update you on how it went, after I’ve done it.

Dancing Men Project 2

Letter frequency analysis project answer B

 

328. Slice of genius

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So, I was doing my usual Human Piechart  activity when an interesting point occurred. I had the class split into a group of 20 and a group of 18 (I had a student in charge of each group so that the circles would be factors of 360). I asked the class how we could combine the groups to make a whole class pie chart. One student suggested we add together the angles and divide by two. Several other students agreed that it was a good idea.

There goes my lesson plan.

I put this prediction on the board and asked them to prove it or disprove it using hard facts. I was very impressed by the different techniques they used. Most students started by adding the angles and dividing by two, then:

  • They went to the raw data and calculated the actual answers, disproving the prediction.
  • Some looked at the angles on the ‘combined’ pie chart and worked out the number of degrees per person for each angle. They used the irregularities in angles to disprove the prediction.
  • Looking at how many degrees there were per person and using logical deduction that you cannot add the angles.
  • Others noticed that categories with the same number of people had different sized angles.

All this before they’d answered a single pie chart question! The moral of this story is: don’t ignore the wrong suggestions, embrace them and use student knowledge to dispel the myths.

322. Accessing Quadratics

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If you teach in the UK and haven’t used the excellent Access Maths site, why not?

Seriously, you are missing out!

I’ve used and recommended to colleagues lots of the Access Maths resources. This is the latest worksheet I’ve downloaded (click on the image to link to the 9-1 GCSE resource page):

Image credit: www.accessmaths.co.uk

I used these pentagonal problems (I believe they are know in pedagogical circles as ‘Fox Diagrams’ – but you try Googling that term and not getting a page of pictures of foxes) with my GCSE class as a two part homework. The first homework was to do the outside skills – if they felt confident they could skip questions, if they needed help they should come and see me. I stressed that they would need to use these techniques to part two and it was their responsibility to make sure they were ready. Part two of the homework was to complete the middle ‘exam’ question in their books in their books, showing the full method.

I actually enjoyed marking this homework as it gave me an insight into how they visualised problems – there were at least four different ways to complete this task. Unusually I made any low achieving student come back and redo their homework in an informal detention. By spending a few minutes reflecting on the skills they’d already practised (or should have practised), every student jumped from 0 or 10% to 100% correct. I did little more than point out where their technique had started to fail them. These students left the extra maths session with big smiles and a sense of achievement.

Inspired by the talented @AccessMaths (you really should follow them on Twitter) I’ve done my own triangular resource on expanding, factorising and solving quadratic equations.

Down the pdf here: Staged Quadratics problems

319. Cunning codebreaker

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Do you like a good codebreaker or crack the safe task? My first choice teacher for ideas is Alutwyche on TES Resources. Seriously, check out his amazing resources and follow him on Twitter (@andylutwyche).

Now the thing with ‘Crack the safe’ tasks is there will be a small group of students who everyone expects to win it. It doesn’t matter how long the code is, there can be an anti-climax when someone wins.

What if you could level the playing field or extend the challenge?

Introducing the ‘Lock out hasp’ – a common tool in the field of electrical safety. A very ingenious tool that you may want to look up. It allows you to add numerous locks to a puzzle – they could be differentiated solutions, they could be staged problems. The choice is yours!

Different

Different hasps have different numbers of holes, different locks have different numbers of digits: the hardware store is your oyster!

315. Mancunian Shapes

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I’ve been at a meeting in the Manchester Chamber of Commerce today and I was fascinated by how sympathetically the building has been renovated and preserved. The plasterwork, tiling, glasswork and carving demonstrated exquisite use of shapes, symmetry and tessellation. Here are a few images that you could use as discussion starter:

Just think of all the shape related problems you could set from each image!

314. Maths is a foreign language 

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If I had £1 for every time I heard ‘I don’t get it!’, I could probably buy a new (modestly sized) car. That phrase is banned in my classroom. What does ‘get’ mean? What is ‘it’? Did you actually read the question?

And there we have it: reading the question.

Today’s little life skill strategy can work for all levels of literacy – because you don’t need any! I’ve taught a lot of students who just shut down when they see wordy questions and don’t look at the big picture – literally. There can be a really obvious diagram and they will skip the question. They just don’t try!

Now as you may be aware, I’m based in Wales in the UK. For those outside the UK, Wales is a principality within Great Britain. Although everyone speaks english, the traditional mother tongue is welsh – it’s particularly spoken in the North/West of the country. If you attend a welsh language school, you can do all your exams in welsh. A GCSE is called a TGAU.

But why am I telling you this?

Well, this means that the WJEC/CBAC exam board publishes their exam papers in welsh and english. Identical papers, different languages. I teach over the border in England, where only one or two students per year can speak welsh. This is where it gets interesting …

I went through a welsh language ‘Mathemateg’ paper and picked out the questions which involved diagrams – I also picked out the matching English questions so I was clear on the questions (not a native welsh speaker, just a learner). I gave my GCSE class the Welsh questions and told them to figure out what was going on. After the initial disbelief they had a really good go at the questions. Their comments included:

‘Well, it’s obvious it’s a tally chart’ 


‘Just fill in the table with the numbers from the pattern’


‘That’s got to be a special type of triangle’ (answer isn’t correct, but idea was)


‘Just use angles in a triangle to work it out’


I was impressed – they were constructively arguing about questions and covering diagrams in good maths. When we went over the questions they were telling me how easy it was, yet the week before they’d skipped questions like the angle problem in an assessment! I explained why I’d done it and told them they didn’t need to keep the worksheets as I’d made my point. I was stunned by the number of students who wanted to take them home to show their parents – they were proud of their problem solving – 16 year olds wanting to show off their Maths skills!

This idea can be used with any bilingual exam board or any language that you speak that the students don’t. It’s a good tool for getting over ‘question blindness ‘ and literacy confidence issues too.

These are the exam papers I used:

WJEC GCSE Maths 

CBAC TGAU Mathemateg

If you look at the web addresses there is one digit difference to differentiate between the languages, meaning if you go on the WJEC english language website you can find the welsh equivalent by swapping a 0 for a 5 in the second to last digit.

311. Sales starter

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Here is a neat little starter photograph (click on the image to enlarge) – get the mini whiteboards at the ready!

Sale price starter

Possible questions

  • How much money could be saved with the different reductions?
  • What are the percentage discounts?
  • What is the price as a percentage of the original?
  • What is the exchange rate between pounds and euros (using the original prices)?
  • What would the sale prices be in Euros?

If you can’t read the data clearly, the prices are: £45, £30, £22.50, £13.50, 70 euros