18:30A'BhuthSeries 1Episode 7: Toirt air falbh gu 20 (Subtraction within 20)BBC ALBA Duration: 15 minutes Fri 20th Nov 2009, 18:30 on BBC ALBACalum works out how much change to give customers from 20p. Show more ContributorsDirector:John J MacIsaacProducer:John J MacIsaacGenresLearningPrimaryBrandA'BhuthSeriesA'Bhuth: Series 1 Source: BBC Online