How long will you live? How should you write down numbers? Who's your ideal partner? How good is our voting system? And what is a differential equation? These are difficult and momentous questions. This issue of Plus has some answers, along with a tour of digital art and the usual range of podcasts, news and reviews.

In this issue...

• Understanding uncertainty: How long will you live?
  It's impossible to give a precise date, but using mortality figures from people similar to you, you can make a confident guess. This article tells you how and has an interactive life expectancy calculator. Do you dare to find out?
• Kissing the frog: A mathematician's guide to mating
  What's your strategy for love? Hold out for The Only One? Or try and avoid the really bad ones? How long should you wait before cutting your losses and settling down with the next best who comes along? John Billingham investigates and saves the national grid in the process.
• Mathematics and democracy: Approving a president
  Much criticism has been levelled at the US voting system, and with this being election year, we're bound to hear more of it. In this article Steven J. Brams proposes an alternative voting system that could help make things more democratic.
• The fabulous positional system
  According to one mathematician, god created the whole numbers, with everything else being the work of humanity. Why, then did god not equip us with a good way of writing them down? Chris Hollings reveals that our number system, much used but rarely praised, is in fact a work of genius and took millennia to evolve.
• Universal pictures
  Peter Markowich is a mathematician who likes to take pictures. At first his two interests seemed completely separate to him, but then he realised that behind every picture there is a mathematical story to tell. Plus went to see him to find out more, and ended up with a pictorial introduction to partial differential equations.
• Digital art
  Computer-generated art is on the rise, and with it comes a further blurring of the boundaries between maths and art. Lewis Dartnell looks at some stunning examples.
• Career interview: Systems engineer
  Chuck Gill caught the space bug as a child when watching Alan Shepherd launch into space. Since then he's worked as a US Air Force navigator, a satellite operator, and in the US intelligence service. These days he's busy reducing carbon emissions and preparing London for the 2012 Olympics. Plus went to see him to find out more about his career.
• Teacher package: Group theory
  This issue's teacher package brings together all Plus articles on group theory, exploring its applications and recent breakthroughs, and giving explicit definitions and examples of groups. It also has some handy links to related problems on our sister site NRICH.

But wait, there's more!

• Draw a map with Queen Griselda
• Learn how to keep inflation down
• And meet some election paradoxes

But we're not done yet!

We are releasing two new podcast episodes in conjunction with the stories in this issue. See the podcast page, or go directly to

• Podcast 12, September 2008: Universal pictures
  Universal power through differential equations.
• Plus Careers Podcast 3, September 2008: Systems engineer
  From satellites to the Olympics, all in one career.

Plus all the latest mathematical news and reviews.

Happy reading from the Plus team!