^{th}update from the world of Maths EduTwitter. Here I summarise some of the latest ideas and resources for teaching maths.

**1. Perpendicular Gradient**

I love this gif demonstrating the relationship between gradients of perpendicular lines, shared by Simon Pampena (@mathemaniac).

Geogebra fans will be pleased to see that Tim Brzezinski (@dynamic_math) made 'Slope Triangle Rotation' to explore this further.

**2. Metric Units**

Next time I teach a lesson on units I'm going to show this five minute video on the history of the metric system. I think it's really interesting.

I discovered this on YouTube after watching The mathematical secrets of Pascal’s triangle which was shared by Cliff Pickover (@pickover).

**3. Calculus Puzzles**

A level teachers will like this Chalkdust post 'Puzzles about calculus' by Matthew Scroggs (@mscroggs).

**4. Displays**

Twitter continues to be a great place to share classroom display ideas. I saw two ideas last week that I particularly like. First, check out Sarah Carter's (@mathequalslove) fantastic mathematical welcome sign.

Second, Claire Mazurkiewicz (@MrsMazzy) put an A level twist on Mel's (@Just_Maths) popular maths periodic table display. I rarely see displays designed for A level classrooms - read about it and download the file here.**5. Shadow Shapes**

The image below has been going round the internet for years (original source unknown). I wrote about it last February in Gems 23. I now use it whenever I teach plans and elevations.

Phil Bruce (@pbrucemaths) was inspired by this image to make a PowerPoint of five more examples. You can download it from his blog here, under "shadow shapes".

**Update**

My last day of term was on Friday (hurrah!)... I know some of you are still at school for a couple more days (nearly there!).

In case you missed any of my recent posts, here they are:

I've used VideoScribe to make a welcome video for Year 7 and an expectations video for Year 11 (you can watch both here) - I did something similar for my first lessons last year and it worked quite well.

If you didn't make it to researchED Maths and Science back in June then you might like to watch some videos of the presentations here.

Please follow @Team_Maths1 if you haven't already - I use this account to tweet maths resources, and my partner in crime Lucy tweets articles and maths jokes. We also offer a resource clinic - ask us for help and we will do what we can to find a suitable maths resource for your lesson.

Do check out the hashtag #DonADay too.

I'll probably blog a bit less frequently than usual over the summer holidays (I've got lots of school work to do... I also hope to make a start on organising #christmaths16... and I want to spend lots of time with my daughters). But I will be using the hashtag #summerblogread to tweet links to posts that you might have missed over the years.

It looks like La Salle are organising another Pie and Maths (see Gems 37 for my write up of the last one) so - depending on the date - I might be there for some summer socialising.

I'll leave you with this question from brilliant.org. There are various approaches (it's pretty straightforward if you can do basic trigonometry) but the solution is interesting. Check out the replies to my tweet here to follow the discussion.

Please follow @Team_Maths1 if you haven't already - I use this account to tweet maths resources, and my partner in crime Lucy tweets articles and maths jokes. We also offer a resource clinic - ask us for help and we will do what we can to find a suitable maths resource for your lesson.

Do check out the hashtag #DonADay too.

If you're a fan of Don Steward's maths resources then check out the #DonADay hashtag. pic.twitter.com/FY73QVo4BX— Jo Morgan (@mathsjem) 21 July 2016

It looks like La Salle are organising another Pie and Maths (see Gems 37 for my write up of the last one) so - depending on the date - I might be there for some summer socialising.

I'll leave you with this question from brilliant.org. There are various approaches (it's pretty straightforward if you can do basic trigonometry) but the solution is interesting. Check out the replies to my tweet here to follow the discussion.