🛠️ Number Cards and Board Build

Right before building, the teacher gives a short mini-lesson on making usable prototype pieces: writing numerals 0-20 clearly, showing quantities with counters, and organizing teen numbers as ten ones and some ones. Pairs then make a low-fidelity prototype using sentence strips, sticky notes, cubes, dot cards, paper clips, and spinners. They create only the pieces needed for one playable round, including a simple rule strip and at least one set of math challenge cards.