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Maths on the Back of an Envelope

Clever ways to (roughly) calculate anything

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Maths on the Back of an Envelope

By: Rob Eastaway
Narrated by: Rob Eastaway
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‘Another terrific book by Rob Eastaway’ SIMON SINGH

‘A delightfully accessible guide to how to play with numbers’ HANNAH FRY

How many cats are there in the world?

What's the chance of winning the lottery twice?

And just how long does it take to count to a million?

Learn how to tackle tricky maths problems with nothing but the back of an envelope, a pencil and some good old-fashioned brain power.

Join Rob Eastaway as he takes an entertaining look at how to figure without a calculator. Packed with amusing anecdotes, quizzes, and handy calculation tips for every situation, Maths on the Back of an Envelope is an invaluable introduction to the art of estimation, and a welcome reminder that sometimes our own brain is the best tool we have to deal with numbers.

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Critic reviews

‘A delightfully accessible guide to how to play with numbers’ – Dr Hannah Fry, author of Hello World and The Mathematics of Love
‘Put aside those calculators and computers, and find a pen and piece of paper! In a collection of riveting tips and examples, Eastaway shows us amazing short-cuts to get rough answers to important questions. I still find it remarkable that 16% of 25 is exactly the same as 25% of 16!’ – Professor Sir David Spiegelhalter, author of The Art of Statistics
‘Another terrific book by Rob Eastaway’ – Simon Singh
‘Packed with fun examples and fresh ideas. I thought I was on top of this subject, but I learned a lot’ – Tim Harford
‘A joyful primer about the lost art of calculating without a calculator’ – Guardian
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Most relevant
If you like numbers, you'll love this book. If you love playing with numbers then you'll really love this book. And when he talks about a technique you already know about, or even better, use, then you will feel a certain degree of pride in being someone who knows how much fun maths can be!

Numerical therapy!

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Excellent introduction and overview of the powers and limits for estimation. As a maths teacher I will be recommending this to a number of my classes. You will also leave with a strong foundation to develop your own 'back of envelope calculation' skills!

Must Read for Lovers of Mathematics!

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The audiobook starts with “There is an accompanying booklet” but there is no such thing

There is no accompanying booklet

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throughout this audio book references are repeatedly made to the "PDF accompanying this audio book", but there isn't one.

No PDFs with Audio Book

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Didn’t finish it. Just lots of stories with a touch of maths but didn’t grab me.

Not what I was expecting

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