As children return to school in England and Wales, we hear about what we know and what we don’t when it comes to Covid-19 risks in school settings. What do the numbers tell us about how well test and trace is working? Will reopening universities really kill 50,000 people? Are the UK’s figures on economic growth as bad as they look? And is maths real? When someone goes viral asking maths questions on social media, More or Less finds answers.