The study investigates effects of a change in teaching of problem-solving classes in first-year Discrete Mathematics in an Australian university. Traditionally, students had two small-group tutorials a week, led by a tutor presenting solutions, in response to questions or to illustrate a particular point. One was replaced by a larger tutor-led class and the other by a board tutorial, in which students collaborated in small groups, working on a board, with a tutor available to answer questions. Achievement scores came from examination scripts. Students from the last year of traditional tutorials were compared with students from the first year of board tutorials, with a split motivated by previous results of the authors, into domestic and international subgroups. Significant results favoured traditional tutorials and domestic students. No significant gender-related differences were found in the collaborative groups.