Maths on the back of an envelope

6.00pm to 7.15pm, Friday 18 October

The Theatre

The Royal Institution of Great Britain GB United Kingdom W1S 4BS 21 Albemarle Street London

This event has already taken place

  • Is there still a place for mental arithmetic in the age of the calculator?

    Credit: Public domain, via


Standard £16


Concession £10


Ri Members and Ri Patrons £7

Event description

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?

Join best-selling maths author Rob Eastaway as he takes an entertaining look at how to figure without a calculator.  With amusing anecdotes, arithmetical challenges, and handy calculations tips, this is an engaging introduction to the essential skills of estimation, and a welcome reminder that sometimes our own brain is the best tool we have to deal with numbers.

About the speaker

Rob Eastaway is an author and speaker whose books include the bestselling Why Do Buses Come In Threes?  and  Maths for Mums and Dads.  He is the Director of Maths Inspiration, a national programme of theatre-based lectures for teenagers.  He regularly appears on BBC Radio 4's More or Less programme, and his puzzles can sometimes be heard on the Today programme.  In 2016 he was awarded the Zeeman Medal for excellence in the communication of maths to the general public.


The doors will open at approximately 5.30pm, with a prompt start at 6.00pm. There will be time for questions after the talk.

Latecomers will be admitted into the gallery.

Book signing

Copies of Rob's books will be available for purchase and signing after the talk.

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