By Leon, Private Tutor, Sponge ME, Maths Tuition Singapore

As the saying goes, “Prevention is better than cure.” I cannot agree with it more. However, avoiding CSMs (Careless Stupid Mistakes) can and will never be 100% full proof – you know and accept this. That doesn’t mean you resign to it without first putting up a good fight. If Plan A fails, there is always Plan B. A backup plan will ensure you keep CSMs to a bare minimal – it’s called checking your answers!

You may be thinking that you barely have time to check your answers, let alone finish your exam papers. Yes, that may be true especially if you lack practice. However, if you make it a habit to carry out *intermediate checks* as you work through your maths problems, you will realise that it is a lot more time efficient compared to checking only at the end.

For instance, if you had to navigate your way across the great oceans using nothing more than a compass – would you only check your compass once at the end of the journey (provided you get there in the first place), or would you be checking your compass intermittently throughout the journey to make sure you are on track? Checking your answers is based on the same logic. By placing so-called mental check points throughout your working steps, you will be able detect an error early, rather than when it’s too late.

Of course, exactly how to check and where to check is a topic best left for another day. But in a nutshell, you should be equipped with a set of ‘check tools’, namely the **Sanity Check** (good for making quick sense of numerical answers), the **Reverse Check** (good for checking algebraic manipulative errors) and the **Loop Check** (good for quickly checking solutions by means of substitution) and learn how to use them effectively. There are also ways to make use of certain features available on the latest approved scientific calculators to double-check not just arithmetic, but also algebraic and statistical calculations.

Once again here are the 5 tips to avoid careless mistakes for your GCE O-Level Mathematics exams:

- Do NOT Skip Steps
- Know Your Tendencies
- Watch Your Units
- Keep It Neat
- Check Your Answers

I hope that you have found this series of posts educational and have realised that though CSMs can’t be entirely eliminated, they can definitely be suppressed with a high level of success and anyone can learn how to do this. All the best for your exams! 😀