As I write this article, there are over 22,000 secondary mathematics resources on TES. That does not include all the primary resources that would also be suitable for high-school students, or the multiple resources contained in some listings. This wealth of free resources, on a scale never seen before, presents us with two problems.

The first is sifting through to find the resource you need. Through my role as TES Secondary Maths Advisor, together with my Maths Panel, we have tried to make this less of an issue by using the Recommended feature to flag-up practically high-quality resources, creating Topic Special collections, hand-picking themed resources for the fortnightly newsletter, and tweeting a Resource of the Day from @TESmaths. All of this is designed to help ensure that the very best resources make it to the top, and reduce your search time to an absolute minimum.

However, this wealth of resources brings with it a far more dangerous problem – an over reliance on other people’s resources.

I remember when I was a PGCE student on my first placement. If I was asked to teach a class the joys of simplifying a fraction, then I might have a quick look on emaths, or ask my mentor if he had anything, but more often than not I would end up spending a fair bit of time at home putting together a PowerPoint, worksheet or Tarsia jigsaw to use in the lesson.

If I was a PGCE student today, my approach to lesson planning would be very different. I would just hop on TES, find someone else’s fractions resource, and use that. Even better if this resource has been rated highly and downloaded thousands of times – it must be good!

The problem is that each resource on TES (and any other website, for that matter) has been created by an individual teacher, with their own unique style, for an individual class with their own unique wants and needs. In its present form, it may not be suitable for use in your lesson. Too many times I have seen teachers deliver lessons that have not gone as well as they would have liked, and then blame the resource – “this is supposed to be 5 stars!”.

In objection to spending time creating your own resources, I often hear people say “there’s no point in re-inventing the wheel”. Whilst that is certainly true, if the wheel you find does not fit your vehicle, then you are likely to be in for a very bumpy ride.

So am I saying that you should never use a resource from TES (I can hear my boss drawing up my P45 as I type)?… I am certainly not. TES contains some of the best maths resources in the world, and my teaching would be a lot poorer without it. No, I am saying that you should use the resources carefully. Download one, read the comments from other users at the bottom of the resource page, and adapt the resource to make it suit your teaching and your students. And when you are done and your lesson goes down a storm, remember share your experience in the comments so we can all learn from each other.