# Mental arithmetic

Being able to do calculations in your head has some obvious uses, like checking your change in the supermarket, or figuring out the scores on the cricket ground. But is it useful for anything else in this age of computers and calculators?

The most important thing mental arithmetic does is to give you a feel for numbers, relationships between them and the patterns they make. This is obviously essential if you want to do well in maths at school, or go on to take a job that uses a lot of maths. But even if you plan to move into a completely different field after school, you will need a good grip on numbers and the ability to solve simple maths problems in your head. It’s a bit like learning a language: even though you can resort to a dictionary whenever you don’t know a word, you will never be able to speak fluently unless you know a lot of the vocabulary off the top of your head.

### A safety net

Doctors and nurses, for example, need to do complicated calculations to work out the doses of the drugs they have to give to their patients. Even if they do have a calculator to hand, they have to be able to spot if they have made a mistake – punching in an extra zero or forgetting a decimal point can lead to the dose being ten times too high or low, with disastrous consequences for the patient. Being good at mental arithmetic is like having a safety-net that will guard you against mistakes.

### Visual imagination

People whose work is very visual, like designers, architects and artists, for example, need to be able to imagine the way three-dimensional objects move in space. A look at a fashion designer’s sketch pad will show you that he or she has an intuitive feel for proportions and perspective. Such a feel for space and the objects in it can only come through practice and experience. The mental arithmetic you learn at school helps you exercise your visual imagination.

### Maths in music

If you play a musical instrument, you will already have learnt how maths is important in music. Certain combinations of sounds are pleasing to us, because of the mathematical relationships between their frequencies. This is all about fractions, and musicians and sound engineers need an intuitive understanding of the relationships between numbers.

These are just three examples of how a good understanding of maths and numbers helps even in areas which, on the face of it, have nothing to do with maths. But also in your private life such an understanding is essential. When you open the paper or switch on the TV, you are bombarded by statistics, issued by politicians to get you to vote for them or by companies to get you to buy their products. When you open your mail, you will find bank statements and bills. You won’t always have the time to sit down and check them with a calculator and a maths book. But if you understand numbers, a quick glance can give you a good indication as to whether what is presented to you makes sense or not. If you’re good at mental arithmetic, you’ll glide much more smoothly through a world that is, after all, made up of numbers and patterns.