Emphasizing using pattern as a strategy, Peterson presents patterns similar to those in figure 1. He claims, " It is necessary to rely on students' assumptions of linearity..."(p.399). If we consider A, we notice this pattern: Each solution is obtained by subtracting 3 from the previous one. Using this logic, it is reasonable to conclude that 3× -1 = 0 - 3 = -3. For B, if we use the same type of pattern logic (except now adding 3 to the previous expression), -3× - 1 = 0 + 3 = 3. It is good for students to recognize patterns. This type of reasoning is important and can lead to a discussion about proof by induction. However,if the discussion is left as is, students may apply this type of pattern logic to other mathematical concepts.
Let me play devil's advocate and consider the following pattern: