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A biologist has developed a blood test for detecting a certain minor abnormality in infants. Obviously if you have blood samples from 100 children, you could find out which children are affected by running 100 separate tests. But mathematicians are never satisfied by the obvious answer. Keith Ball uses information theory to explain how to cut down the number of tests significantly, by
pooling samples of blood.

John Allen Paulos is the man who popularised the word "innumeracy", meaning the alltoocommon condition of ignorance and bewilderment about maths and numbers in general. A light, cheerful and eversoslightly smug look at the problem, his bestknown book of the same name (reviewed in Issue 11 of Plus) traces the roots of innumeracy to poor teaching and offers suggestions for antidotes and innoculation.

Are you interested in maths just for the fun of it? Or does mathematics seem irrelevant? Either way, this book is for you. Keith Ball is eager to share with his readers the way some of the numbers around us in the world work, and their uses.


In this issue we talk to maths student Emily Dixon about her university studies, and where maths might take her in the future.



The concept of a speed limit seems a simple one  until you think what can happen when a speed camera clocks a rotating wheel...

Following on from his article 'The prime number lottery' in last issue of Plus, Marcus du Sautoy continues his exploration of the greatest unsolved problem of mathematics: The Riemann Hypothesis.

Calculus is a collection of tools, such as differentiation and integration, for solving problems in mathematics which involve "rates of change" and "areas". In the second of two articles aimed specially at students meeting calculus for the first time, Chris Sangwin tells us how to move on from first principles to differentiation as we know and love it!
