KS2 maths puzzles: Secret Agent maths

Are you ready to uncover dastardly deeds and confront super-evil villains, armed just with your mathematical skills and lots of courage? Join Oscar Octo and Penelope Penta, agents for the Geometric World Spy Agency, to track down a mysterious nemesis. There'll be a few (ok, a load!) of number puzzles to solve along the way, all designed to challenge KS2 mathematicians to the limit. Will you accept your mission?