Part I

Whole Numbers: The Building Blocks of Maths

In this part . . .

If you can count, you can do maths.

Itâs helpful to build up shortcuts to make maths easier, though â and thatâs what this part is all about: making maths easier. I show you how to stay calm and focused (and shut up the little voices telling you you canât do maths) and then help you figure out how to add, take away, multiply and divide whole numbers â the sums all of the others are based on.

You need to be able to see if your answer looks right: to do that, you need to be able to round off and to estimate so that you donât say something daft like âThe Eiffel Tower is four centimetres tallâ.

Chapter 1

Getting Started

In This Chapter

Realising you can already do maths Working with whole numbers Fathoming fractions, percentages and the like (with added pizza) Before you read any more of this book, take a big, deep breath. I know what taking on something difficult or frightening feels like â I feel just the same about dance classes, and I still have to steel myself a bit when I go into a supermarket.

I start this chapter by saying thanks â thanks for giving maths a try and thanks for listening to me. Iâm not the kind of maths teacher who wears tweed jackets with leather patches and yells at you when you donât pick up on his mumbles straight away. I want to help you get past the fear and the mind blanks and show you not just that you can do maths well, but that you already do maths well and can use that base to build upon. I show you how, with a bit of work, you can master the bits and pieces of maths you donât have down to a tee. Youâre smart. I believe in you.

Perhaps you find the maths you do in day-to-day life so easy you donât even notice youâre doing sums. I spend some time in this chapter showing you what you already know and then introduce the topics I cover in the rest of the book.

Youâre Already Good at Maths

Put your hand up if youâve ever said something like âIâm no good at maths.â I promise I wonât yell at you. Now imagine saying âIâm no good at talkingâ or âIâm no good at walking.â Those things may be true at times â I get tongue-tied once in a while, and Iâve been known to trip over invisible objects â but most of the time my mumbling and stumbling are perfectly adequate to get by. I bet the same thing applies with your maths. Maybe you freeze up when you see a fraction or just nod and smile politely when someone shows you a pie chart. This doesnât mean youâre bad at maths, just that you trip up once in a while.

If you can shift your thoughts on maths from âIâm no good at thisâ to âIâm still getting to grips with thisâ, youâll create a self-fulfilling prophecy and begin to understand maths.

Part of the problem may be that you donât realise how much of what you do every day involves doing maths in your head. You may not think youâre doing maths when you judge whether to cross the road on a red light, but your brain is really doing a series of complex calculations and asking questions such as:

How fast is that bus going, and how far away is it? How long will the bus take to get here? How wide is the road, and how long will it take for me to get across? Whatâs the probability of that driver slowing down to avoid me if Iâm in the road? How badly do I want to avoid being honked at or run over? What are the survival and recovery rates for my local hospital? How soon do I need to be where Iâm going? How much time will crossing now save over waiting for the light to change? You do all of these calculations â very roughly â in your head, without a calculator, and without freezing up and saying âIâm no good at maths.â If you regularly got any of those sums wrong â the speedâdistanceâtime analysis, the probability or the game theory â youâd be reading this in hospital and trying to figure out what the jagged line graph at the end of the bed means. (Turn to Chapter 16 if this really is the case â and get well soon!)

So before you cross the road on your way to work, you solve as many as six âimpossibleâ sums in your head, maybe before youâve even had breakfast.

Your First Homework Assignment

Iâm not a big one for setting homework, but Iâm going to ask you to do one thing for me (and, more importantly, for yourself): if you ever find yourself in a situation where you feel like saying âIâm no good at mathsâ, catch yourself and say something else. Try âI used to struggle with maths, but Iâm discovering that maths is easier than I thoughtâ, or âIâm fine with day-to-day mathsâ, or âI really recommend Basic Maths For Dummies: this book turned me into a mathematical genius.â

Although mathematicians traditionally wear rubbish clothes, thick glasses and a bad comb...