A reader, concerned for a friend sitting GCSE, asks:

A friend of mine needs to pass GCSE maths for his uni course and is struggling – any tips on books/sites? He’s just failed the Foundation so he’s now going for the Higher as the score needed for a C is lower.

First up: way to go! Going back to study maths again is a big step, and a big obstacle - but deciding you need it and going for it is the way forward. So, good luck.

Here’s how I’d plan to get the GCSE C you need in the summer.

1. Don’t aim too high

This is a controversial one, but I’m currently dedicating my life to annoying Michael Gove, so bear with it. If you ‘just’ need a C to get into university, don’t try to cram everything in at once - at least until you have the basics mastered. Trying to cover vectors without decent algebra skills is probably more than you want to bite off.

If you’re doing a typical linear GCSE higher paper, the grade boundary for a C is usually about 20-30% overall. I’m not saying you should aim for 30%, that’s a really risky strategy. Instead, aim to get half of the syllabus down perfectly and be familiar enough with the rest that you can pick up the odd mark. If you manage that, your C should be pretty much nailed on.

2. Eat from the Table of Joy

The Table of Joy is the single most useful tool for GCSE maths. You can use it for percentages, pie charts, proportion, ratios and histograms just off the top of my head; with a bit of work, you can do trigonometry, inverse proportion, even some algebraic rearrangement. It’s a handy little badger.

When I first wrote about the Table of Joy, I looked through a GCSE paper and found you could use it for 22% of the marks. Think about that a moment: if you master the Table of Joy, you can pick up pretty much all of the points you need for your C.

But I’m not going to explain it here. You can read more about the Table of Joy in any of my For Dummies books…

3. Learn your formulas and factoids

There are quite a few formulas and mnemonics you need to be on top of to do well at GCSE: areas and perimeters of shapes, formulas for proportion, formula triangles for speed-distance-time and density-mass-volume, SOHCAHTOA, BODMAS((which is bollocks’)) … it gets overwhelming quite quickly.

The thing to do is to write down everything on cards as you learn it. Description on one side, answer on the other. Whenever you get a moment, flick through the cards and test yourself – if you get the answer right, put the card to one side; if you get it wrong, put it to the back. See how quickly you can get through all the cards. If you get through them all without a mistake, treat yourself to a chocolate.

4. Celebrate your mistakes

This is an odd one, but hear me out. It’s really easy, when you’re studying, to get super-down on yourself and think “I can’t do this sum therefore I can’t do maths therefore I’m a worthless human being and I may as well go and sit in a ditch and wait for rain.”

That’s not a helpful attitude.

Instead, when you mess up, do an Andy Murray fist-pump and say “YES! I screwed up. Now I get to fix it.”

Everyone makes mistakes. Some readers of Numeracy Tests For Dummies have been kind enough to point out that I’ve made mistakes in it. Hooray! I get to put them right for the next edition. Compared to drowning in a ditch, it’s much healthier – and makes the editing much less of a chore.

5. Practise relentlessly

If you want to get good at football, you play lots of football. If you want to get good at writing, you do lots of writing. And if you want to get good at maths… guess what? The easiest way is to do lots of maths.

Do a little every day. Push yourself a little further each time. Make sure you keep the basics in mind. You’ll find that a little at a time soon adds up and you’ll be flying through your GCSE in no time.

Good luck!

* Edited 2015-10-27 to fix a footnote.