Over the past fifty years computers have changed the lives of almost everybody on this Planet in very many ways. But if you have read almost any of my Maths Pages you will realise that it is the pocket scientific calculator rather than the computer which has revolutionised the way maths is taught and used in schools, and the way in which maths is used by most people after school.
Since I retired from full-time teaching I have been doing private tutoring. What concerns and saddens me is how little most of my students know about how their pocket scientific calculator works and how to get the best out of it.
These Pages set out to provide some information about pocket scientific calculators. They are intended mainly for school students aged 11 to 16 working towards school examinations. They are not intended for children under 11 or other people using only basic calculators. The difference between a basic and a scientific calculator is described in Getting Started. Throughout most of these Pages “calculator” by itself means a pocket scientific calculator.
All of these Pages assume that you have a pocket scientific calculator in front of you when you are reading them. Like most Pages on my web site they all start with simple ideas but work through to much more advanced ideas - just stop when you have read as much as you need at that particular moment. For this reason there may be links on each Page back to earlier Sections on that Page or to earlier Pages but not always to later Sections or Pages.
There are many different makes and models of pocket scientific calculator, and I have tried to make most Pages as general as possible. Sometimes however I have had to describe how a particular make of calculator works, and this is explained on the Page on Getting Started. If your calculator is not exactly the one I have described it may work slightly differently and you might need to refer to the instructions which came with it.
Your pocket scientific calculator has made it possible for you to carry out types of calculations, particularly in statistics and those involving irrational numbers, in maths, science, geography and many other school subjects, which no one over fifty today could have attempted when they were at school. (Irrational numbers are explained in the Page on Natural Numbers.) But this does not mean that you do not have to learn or remember how to do quick and simple calculations or approximations in your head or with pencil and paper. You should always be allowed to use your calculator in exams like science and geography, but there are still non-calculator papers in maths exams so make sure you are well prepared for them, and of course for the Real World after school.
In particular, if you press the wrong key on your calculator you will get the wrong answer. You will not usually be able to check that it is right by redoing the sum in your head, but you should always do a quick check to make sure that it is sensible.
Each year new calculators come out, and they are getting not only cheaper but also more powerful, that is, they allow you to do more and more things, not just adding, subtracting, multiplying and dividing. Fifty years ago calculators were little more than tools to do simple sums, to speed up routine office calculations or to help people who were not very good at doing sums in their head, and were despised by all serious mathematicians. But over the years they have grown more sophisticated and today they are an indispensible part of the equipment of even the most serious and advanced mathematicians.
Many people over fifty have not yet understood this: “We never had calculators in my day, we were taught to do sums in our head. Young people these days are just plain lazy.”
One of the consequences of the increasing power of today’s calculators and their increasing use by serious mathematicians is that their designers have needed to be very much more rigorous about ensuring that their calculators work according to the strict Rules of Maths than some earlier calculators were: we have what might be referred to as “generations” of calculators, for example we can have G3 and G4 calculators in the same way that we can have G3 and G4 smartphones. So sometimes a G3 calculator will work in a different way to a G4 calculator. Even different models of Casio fx 83 calculators work in different ways, and the instructions with your calculator warn you about this.
Leading on from this, many of the designers of smartphones and tablets and the writers of the Apps for them have not yet caught up with this, and so these may sometimes give wrong answers to some types of calculation; many more of them are just very badly written and give the wrong answer to even the simplest of calculations or, worse still, give a valid answer even if you type in rubbish. By all means use them to work out your fuel consumption or the total cost of a concert but never use them in an exam - you will probably not be allowed to in any case - or in other situations where the wrong answer might have a bad result.
Finally (promise not to laugh), on the day of an exam always double-check to make sure what you have put into your schoolbag is your calculator and not the remote control for your dvd player. I thought you promised not to laugh! - it really does happen, and when it happens to you it is Not Funny.
If you think these Pages are a total waste of space, that teenage boys and girls are already complete experts on every aspect of using scientific pocket calculators, and old men can teach them nothing at all about them, please e-mail me. But if in fact you do find these Pages helpful I would be grateful if you would tell me so, and tell your friends too.
