—Examining the Impact of a Mental Computation Classroom Intervention on the Relational Thinking of Seventh-Grade Students

The present study examined the impact of a mental computation intervention on the relational thinking and equivalence knowledge of seventh-grade students. The instructional intervention focused on classroom discussions, the sharing of mental computation strategies, and conceptual scaffolding from the teacher. A multiple baseline design was used with 66 students in three classes. In each class, students were assessed at five time points on (a) mental computation, (b) mathematical equivalence problem solving, and (c) relational thinking, which was assessed by asking students to make judgments about true-false number sentences. Students in one class improved on equivalence problem solving after the intervention, although ceiling effects mitigated the observation of potential instructional benefits. All students improved their relational thinking skills, and performance paralleled observed gains in mental computation in two of the three classes. Relational thinking performance levels were maintained for up to 12 weeks. The link between mental mathematics and relational thinking implies that mental computation should play a more prominent role in the seventh-grade mathematics classroom.