Learning goals
- The distributive property is geometric: (10+2)(10+3) = 10×10 + 10×3 + 2×10 + 2×3 = 100 + 30 + 20 + 6 = 156.
- Splitting at the tens place makes mental math easy. 23×11 = (20+3)×(10+1) = 200 + 20 + 30 + 3 = 253.
- This is the visual foundation for polynomial multiplication in algebra: (x+2)(x+3) = x² + 5x + 6 uses the same four-region grid.