Take the Rishi Sunak maths challenge

Rishi Sunak is back in the headlines today, saying it’s time for greater maths literacy. But when it comes to his own political pledges, how many of those stand up to mathematical scrutiny? A Spectator mug for the first person to complete all challenges.  

1. The first of Sunak’s five pledges is to ‘reduce debt’. Using published OBR data and basic maths rules, explain whether he is doing so. Show working. 
2. What devices can politicians use to dress up rising debt as falling debt? Would such methods pass muster in a GCSE exam?
3. Sunak says that he will ‘grow the economy’. How many prime ministers in modern history have failed to preside over economic growth? Show sources.
4. Sunak claims that he will ‘halve inflation’. What evidence is there that his policies are having any impact over and above what was forecast to happen when Boris Johnson was prime minister? In which other countries is inflation also expected to halve? Show sources.