Introduction

The story of this book begins on 25 January 2002,

when the German Mathematical Society decided

to hold a dinner to bring together the society’s

oﬃcers and a group of journalists. The agenda was

a conversation about the image of mathematics in

the world at large. One of the participants was Dr.

Norbert Lossau, science editor for the newspaper

Die Welt, with whom I met again several months

later. Out of these conversations arose the idea of

a regular column on mathematics.

I put together an extensive proposal, in which about 150 possible

topics were sketched. My suggestion of “Five-Minute Mathematics”

as the title of the column was accepted, the graphic designers came

up with a logo, and the ﬁrst column appeared in the Monday, 12

May 2003, edition of Die Welt. And so it went week after week, with

the rhythm being broken only when Monday was a holiday and the

newspaper did not appear. After two years and one hundred columns,

“Five-Minute Mathematics” yielded to another column.

In my selection of topics I have attempted to think particularly

of readers who left school long ago and perhaps have no concrete

memory traces of the subject yet would like to learn something about

mathematics. Should the quadratic formula and curve sketching be

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