The results from the test items are shown in Table 3. Here it can be seen that more students gave responses that were classified in the sound understanding (SU) category, after the teaching intervention. For example, the percentage of students’ responses in this category for problem 1 changed from 12%, to 90% for pre- and post-test scores. Similarly, students’ responses that were classified as specific misconceptions (SM) decreased from pre-test to post-test. For example, the percentage of students’ responses in this category for problem 2 changed from 86%, to 29% for pre- and post-test scores.