As maths educators, we want our students to be able to analyse and evaluate various mathematical representations. We also need them to  analyse their own thinking. Often, comparing two strategies or drawings and paying close attention to detail can help students to understand more about how mathematics works.

Asking “What’s the same, what’s different?” helps to stimulate discussion of slides such as this, which focuses on the  equivalence of the two expressions for a fish and chip shop order in Knowing the Unknown (A1).

This slide supports an informal expansion of brackets. While the expressions are mathematically equivalent, this is not the same as saying they are identical, and the question “are the two expressions the same” may elicit different responses because of this.