03:30Maths ChallengeMaths Challenge 1Addition and subtraction of the number 9School Radio Duration: 15 minutes Fri 10th Oct 2014, 03:30 on School RadioAvailable for over a yearListen nowRalph van Dijk and side-kick Matrix have more questions to consolidate mental maths skills and the focus today is adding and subtracting the number 9.GenresLearningPrimaryBrandMaths ChallengeSeriesMaths Challenge: Maths Challenge 1 Source: BBC Online