The mean scores for each of the six basic steps of the problem solving routine of problem A at T1, T2 and T3 are given in Annex 1a and visualised in Figure 1. At T1 there was no difference between study and control groups for each of the six steps in the problem-solving routine, with a total mean score 6.76 versus 7.14 (maximum score 3 points per step, 18 in total). At T2 the study group showed significantly higher scores than the control group (11.88 vs 7.24). At T3 the study group again scored significantly higher on all steps compared to control students (12.23 vs 7.77), and also when compared to their own previous results at T1.

Results of the matched pair analysis for each of the six steps in problem A are given in Annex 1b, presenting the average increase in student scores in the study group between T1 and T2, and between T1 and T3, when compared with those in the control group.