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Tuesday 14 October 2014

Percentages with Dragons!

I don't have many differing resources for Percentages. It's probably up there with basic operations as the most important part of Mathematics to our learners, but since this is the case, there are bags of resources online to support with this.

I have two resources to add that are a little bit different:

Some higher level thinking and problem solving with percentages:




Next is my Dragon's Den percentages: It is for reviewing / revising percentages and there is a difficult one (with various compound interest calculations) and a more simpler one for practising basic increase and decrease.

Basically - the students invest a portion of their 10k into a choice of three companies. They can choose to invest in two if they like, but not all three.
After everyone has written in their investment choice on the attached sheet, they then work out the money they have made or lost. There is an example on the sheet, but I think it relates only to the higher powerpoint. Also, be warned that I teach to a point where we use multipliers, so if you don't do that you might have to tweak your answer sheet.
The biggest obstacle I have run into when running this activity is that students don't carry over the money correctly into the next round. 

All the companies exist (or have been pitched in the den) - and if I have given them a green, then they have had investment and may have been successful.

I trust my students to check each others work each round, and we take time to go through the workings at the end of each round. They will also never run out of money - as they just lose a percentage of their investment.

The best round is number two - none of the investment opportunities are worthwhile. The students did not need to invest in any if they don't want!


All the bits are available here:

Percentages - Dragon's Den and Other Problems


Finally - I'm sure you all know this clip: but it is a great plenary. The teacher doesn't know - but does anyone in your class?


The video is available via the link above as well.


Sunday 5 October 2014

Prime Numbers, Factors and Prime Factors

Here are some resources and ideas I use when teaching topics involving Primes and Prime Factors.

There are a few ways of spotting prime numbers - including Sieve of Eratosthenes, which I still think is a bit forced.

I like the links to Area (which they may not make straight away, depending on ability). I recommend doing this using multilink cubes: Idea taken from Don Steward


I give 25 cubes and ask the students to record how many ways they could rearrange cubes to represent the numbers from 1 - 25:


Then this leads to discussions about Factors, Square Numbers and what it takes to be a prime number.

If you want to go onto Prime factorisation, then try it a different way - show how powerful prime numbers can be. Set a target - make it a game - after a while allow them to choose one more number to add to the list. Ask them why they wanted that number..



Then comes lots of different activities:



Collective Memory - have the students copy the image down from memory and then fill in the numbers when done.



I can't believe I have never heard of Shikaku until this week. It is also referred to as rectangles. It's so perfect to consolidate factors (i.e. knowing that 10 could be one strip of ten or two strips of five) and also help with Area too.
This website allows you to choose loads of different levels of difficulty, meaning differentiation is easy! Also can be done on the website (with timings for extra competition) or printed. There are also a bunch of apps too with the game.


My last resource this post is Factors bingo - if you haven't played this before I will be surprised, but nevertheless here are the rules:



Other places to look for resources on this include, as usual, Don Steward's median blog.

Also check out some good Factor resources on resourceaholic

My last comment is really about selling this topic, particularly primes. There are lots of interesting research and books about prime numbers, and whilst much of it would go over many student's heads, I still think there is value in you discussing that these things are out there. Sound enthused about things you have read, the fact that there are monetary prizes for finding primes, or that internet encryption is based on the idea that no-one has found a quick way to check if a number is a prime number.

Thanks - any other good links then let me know!