Exclusions, black holes and dividing by zero

Do half of children in Wales have special educational needs? Are permanent exclusions at the highest ever level in England? Labour are talking about a £22bn black hole. Is that a new black hole in the finances? Are there more Ghanaian nurses in the UK than in Ghana? Can you divide one by zero?Tim Harford looks at some of the numbers in the news.Presenter: Tim Harford Reporters: Kate Lamble and Nathan Gower Producer: Beth Ashmead Latham Series producer: Tom Colls Production co-ordinator: Katie Morrison Sound mix: Andy Fell Editor: Richard Vadon