Maths on the Back of an Envelope: Clever Ways to (Roughly) Calculate Anything by Rob Eastaway: Book of the Week

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.

Maths on the Back of an Envelope: Clever Ways to (Roughly) Calculate Anything by Rob Eastaway (RRP £9.99) is available in Bookmark in The Crescent, Spalding, at £7.99. There's a further 20% discount with the voucher in this week's Spalding Guardian (on sale October 10-16).