^{rd}gems post. This is where I share some of the latest news, ideas and resources for maths teachers. It's the summer holidays! Many of you will be on a Twitter break right now, so this post will fill you in on some things you might have missed in the last couple of weeks.

It was in the summer holidays - four years ago this week- that I first started writing my gems posts. You can see the full collection here.

**1. Triangles**

Thanks to John Rowe (@MrJohnRowe) for sharing this right-angled trigonometry activity. Students have the find the length

*x*.

Benjamin Leis (@benjamin_leis) has blogged about his approach to this problem here.

If you like this then you might also enjoy this problem from UEA which requires knowledge of the sine and cosine rules - I featured it in Gems 54. It takes a while to solve!

You might also like the angle chase problems I shared in Gems 35. I love angle chases!

Speaking of triangles, thanks to Mark Horley (@mhorley) for sharing @DrPMaths' triangle generator. This helpful tool creates possible triangles with integer sides, area and height. If you make your own resources then this will be helpful to ensure you don't include impossible triangles.

**2. Sums and Products**

Thanks to Shaun Carter (@theshauncarter) for sharing a new resource which he calls 'Diamond Problems'. He blogged about it here.

The questions are similar to those on this shorter 'Sum Products' worksheet which I always use before my students start factorising quadratics. Of course, as Shaun says in his post, these puzzles are suitable for students of any age even if they're not studying quadratics - they are good practice for working with negative numbers and decimals.

Thanks also to Meredith Purser (@MeredithPurser) for suggesting that students first work out the rule themselves before completing the blank grids.

We present this as a puzzle before showing the actual rule! The Ss LOVE the challenge of figuring out what the pattern is. Lots of gasps and reminders NOT to give it away. :) pic.twitter.com/VDgGQTdzoq— Meredith Purser (@MeredithPurser) 21 July 2018

**3. #midweekmaths**

The White Rose Maths Secondary Twitter account (@WRMathsSec) is sharing a weekly problem throughout the holidays using the hashtag #midweekmaths.

It's worth following @WRMathsSec because they regularly share lovely tasks for students.

Also check out their new secondary five year plan.

I have always set homeworks that directly relate to the topic I'm teaching, but for the last couple of years I have been meaning to change that. Continually revisiting past topics through homework is a great way to help students remember things.

Thanks to David Wees (@davidwees) for sharing 125 interleaved practice assignments - although these are aligned to a specific curriculum, it's so helpful to see the format and approach. This is definitely on my list of things to start doing!

I know many of you already use Geogebra, but you might not have seen this beta version of Geogebra Whiteboard. Thanks to Pip (@AccomplishEdu) for sharing this. The interface is brilliant - it's so easy to construct and annotate diagrams. Have a play with it and you'll see what I mean.

I've updated my conference listings for 2018/19. There are lots of great events coming up. Next term I intend to go to #mathsconf17 and MathsJam. And I hope to announce my own event soon...

I've been working on my A level resource libraries - they need a total rewrite because of the new A level specifications. It's a huge, time consuming job!

If you're a member of The Mathematical Association and interested in volunteering, please get in touch. I chair the Publicity and Media Committee and am looking for a couple of new members of my committee. I'm also looking for people to help man the MA bookstand at conferences. Please let me know if you can help. A small honorarium will be paid to conference volunteers.

In other news:

I'll leave you with this arithmetic maze from @MathforLove, shared by @MathsEdIdeas. Without passing through the same cell twice, what’s the largest total you can make? This might be a nice activity for Year 7 to have a go at in September.

**4. Interleaved Homework**I have always set homeworks that directly relate to the topic I'm teaching, but for the last couple of years I have been meaning to change that. Continually revisiting past topics through homework is a great way to help students remember things.

Thanks to David Wees (@davidwees) for sharing 125 interleaved practice assignments - although these are aligned to a specific curriculum, it's so helpful to see the format and approach. This is definitely on my list of things to start doing!

**5. Geogebra Whiteboard**I know many of you already use Geogebra, but you might not have seen this beta version of Geogebra Whiteboard. Thanks to Pip (@AccomplishEdu) for sharing this. The interface is brilliant - it's so easy to construct and annotate diagrams. Have a play with it and you'll see what I mean.

Many maths 'revision' videos just tell students procedures, assume understanding & student's repeat the procedure. Playing with new @geogebra IWB I have created this little 'interactive'- intended as a reminder to the student not a procedure to follow. When you think you learn! pic.twitter.com/tiOj0JjMjK— Pip - Mathematics (@AccomplishEdu) 3 August 2018

**Update**I've updated my conference listings for 2018/19. There are lots of great events coming up. Next term I intend to go to #mathsconf17 and MathsJam. And I hope to announce my own event soon...

I've been working on my A level resource libraries - they need a total rewrite because of the new A level specifications. It's a huge, time consuming job!

If you're a member of The Mathematical Association and interested in volunteering, please get in touch. I chair the Publicity and Media Committee and am looking for a couple of new members of my committee. I'm also looking for people to help man the MA bookstand at conferences. Please let me know if you can help. A small honorarium will be paid to conference volunteers.

In other news:

- Corbettmaths (@Corbettmaths) has made his new Corbettmaths Primary website live. It features loads of videos, question papers and 5-a-days.
- The MA's latest Equals Magazine has been published. This free magazine focuses on maths and SEND.
- Read this great article "How to Talk About the Fields Medal at Your Next Cocktail Party" by Evelyn Lamb.
- You'll also enjoy this brilliant post from Alan Parr "... Tables Not Well Known" about teaching times tables in the 1800s.
- Congratulations to Nira Chamberlain, winner of the #bigmathoff. You can read a final write-up of the competition here.

I'll leave you with this arithmetic maze from @MathforLove, shared by @MathsEdIdeas. Without passing through the same cell twice, what’s the largest total you can make? This might be a nice activity for Year 7 to have a go at in September.