The evidence so far suggests that interleaving is likely applicable not just to math, but to almost any topic or skill. Badminton. History (mix concepts from related periods). Basketball (practice around the free throw line, not repeatedly from the line). Biology. Piano. Chemistry. Skateboarding. Blindfolded beanbag throwing, for heaven’s sake. Certainly any material taught in a single semester, in any single course, is a ripe target for interleaving. You have to review the material anyway at some point.
