Kjartan Poskitt was born in York and is an author and TV presenter. His best-known books are the Murderous Maths non-fiction series and the novels about Urgum the Axeman. He has also written songs and plays, annuals, quiz books, and for television.

Seeking shelter from a storm, your troubles have only multiplied. . . . Can you get to grip with numbers and Escape from Hotel Infinity?