In light of the Royal pregnancy Tim Harford asks what severe morning sickness tells us about the chances of having twins. Yan Wong helps him look at the figures. We disentangle the Chancellor' Autumn Statement and ask: where is the economy really at? As Nigeria prepares to revise its GDP statistics with an expected jump of 40-60%, we ask how reliable are African GDP statistics? Another Daily Telegraph headline comes under scrutiny. And we return to our Lego tower and look at how Lego can be used to teach maths with Eugenia Cheng of Sheffiled University.