Before students can work flexibly with ratios, they must be able to answer a more fundamental question: What exactly are we comparing, and why? In this episode, we zoom in on the core comparison structures that sit beneath ratios, proportions, geometry, and algebra: part-to-part relationships, part-to-whole relationships, and unit reasoning. You’ll hear how these ways of thinking develop over time, how they connect back to geometry through reference points, structure, and scale, and why the n...