I have added a new link Learning on the right hand side which is a collection of general articles / useful links on learning and studying.
Valentine’s Day is coming…
Click on the image and then on the slider!
Why not send your mathematical friends (or anybody else!) a Desmos Valentine? The wonderful team at Desmos have made their brilliant math-o-grams available earlier this year….and watch out for new designs coming soon.
The math-o-grams are really easy to create; why not give it a try? Just select your design, add your message and share!
Regression
If you want to check your calculations for a regression line and see the line then Excel and WolframAlpha are both very easy to use. In Excel – just add the data, insert a chart – choose Scatter, then add a trend line.
…or let WolframAlpha do all the work for you (including a plot)!
WolframAlpha Regression
You could also use Desmos. Their video gives clear instructions:
For another example with an A Level question (using the same data as for Excel and WolframAlpha above) check this slideshow.
Transum Maths Puzzles
If you enjoy puzzles try Pu Wiang from Transum
Update: 19 is the new record!
Select Image for Transum’s Pu Wiange puzzle
I couldn’t resist this counter moving challenge – happy to report that I scored 20! Evidence in the image!
You can try more puzzles from Transum here.
There are plenty to try, all are attractively presented and easy to use. Fun to do but these puzzles will help students practise a variety of mathematical skills.
Some of these puzzles would make good lesson starters, for example the Magic Square puzzle or Prime Square.
Note – this has been added to the Puzzles page.
Desmos on Android
The best graphing calculator around is now available on Android (free). Get it on Google play here. (Desmos iOS apps have been available for some time).
Maths students everywhere get this app! It’s great for younger students as it is easy to use for learning about graphs but has the sophisticated features that older students need. From simple linear graphs to polar or parametric curves – Desmos does it all!
There are several examples in the slideshows here to show you the syntax you need on Desmos if you are unfamiliar with it.
It’s Christmas time!
So,
time to relax and what better way to relax than with a puzzle or two?!
On Nrich you’ll find a collection of advent calendars a Sudoku for each day perhaps? (Solutions are supplied if you want them). Or a tangram? Maybe you want to play a game? (Clearly the year doesn’t matter for an Advent Calendar!)
Plus Magazine also have an Advent Calendar where you will find some of their favourite books and other mathematical toys.
For many more games and puzzles, see this collection including a challenging logic puzzle from Coolmath Games – can you set the circuits to light up that Christmas tree?! If any of you have any little relatives they might enjoy Top Marks’ collection of their favourite Christmas Activities.
Perhaps you could make your Mathematical friends some cards! Why not put a Desmos tree on the 
cover?! Note this is simply a collection of lines and circles, as you can see from the syntax it is very easy to restrict x or y values. (For more on getting creative with Desmos, see Graph Art).
Staying with the subject of cards you can practise your coding skills with this Scratch project with a very clear tutorial on how to make a greeting card; not a great work, but I did enjoy playing with Scratch: here’s one I made earlier! If you are feeling creative you might like these Christmas fonts.
On the subject of coding and Christmas trees you might enjoy Holiday Lights where you can use coding to light up a holiday tree outside The White House. Holiday Lights comes from Google as part of their Made With Code initiative. Note that Google’s Blockly is being used for the code.
For some rather more advanced coding, there’s a rather nice Christmas tree generator here; select Auto Generate and sit back and admire the tree! Note that for any Scratch project you can ‘look inside’ and see the coding – a good way to learn more syntax.
Scratch project by vidarfw02
Wishing students (and their teachers!) everywhere a very Happy Christmas.
Spirograph
Inspirograph by Nathan Friend
As a child my Spirograph was definitely a favourite toy so I was delighted to find this digital version, Inspirograph by Nathan Friend. Try altering the gears so that the fixed and rotating gear are the same size, or make one size a factor of the other, make the two sizes have a common factor, or not! Investigate. You can change the colours too and create a work of Art! For some more Spirograph resources including from the awesome Desmos graphing calculator see this post. 
Gradients and Straight Lines
The gradient of a straight line
Use the excellent Desmos graphing calculator to explore the gradient of a straight line. Select the image then you can change the sliders for m and c to change the line and drag the points so you can verify the gradient of the line.
See also Explore Straight Lines.
Quadratic Inequalities
Select image for the Desmos page
To solve a quadratic inequality such as x2-6x+8>0 the best approach is to find the critical values of x which make the value of the function 0 and sketch the graph. Here we can factorise so we see that we require (x-2)(x-4)>0 We are looking for values of x to make x2-6x+8 positive. We see that y is positive when x>4 and when x<2.
Note the link to another Desmos page where you can look at further quadratic functions.
Select image to experiment
If you wish to see some worked examples and try some exercises you could check The Maths Teacher – See Algebra AS Level – Inequalities: Linear and Quadratic. Note the choice of video / transcript or go straight to the exercise with worked solutions. You may find other useful resources here too.
You could of course use WolframAlpha to check the solution to any inequalities and generate as many examples as you want. Simply type in the inequality and plot as well as the he solutions will be returned.
Select image for query on WolframAlpha
Matrices Resources
A new slideshow on matrices has been added to the WolframAlpha series.
Matrices
See the spreadsheets by Mike Hadden MatrixDeterimant and MatrixInverse, these enable you to check answers and see working out as well.
If you are looking for notes and examples on Matrices then the following are useful sources and appropriate for Advanced and degree level students.
Notes and examples
Chapter 9 on Matrices and Transformations from the CIMT Further Pure Mathematics A Level material,
Just the Maths,
The Math Centre
and The HELM Project. If you have not come across the HELM Project before, the project was designed to support the mathematical education of engineering students and includes an extensive collection of notes which include clear worked examples. You can see on the list that a very small number of titles are ‘not ready yet'; for the sake of completeness the complete set is hosted by the Open University. To access the Open University resources you will need to create an account (easy and free), this will also give you access to the numerous free online courses.
