Math Billiards

Quick Teacher Tips

Key vocabulary

• complementary angles: two angles whose measures add to 90°
• supplementary angles: two angles whose measures add to 180°; two of them side by side on a straight line form a linear pair
• vertical angles: the angles across from each other where two lines cross; they are equal
• transversal: a line that crosses two or more other lines (here, the line of the shot)
• corresponding, alternate interior and alternate exterior angles: equal when the lines are parallel; same-side interior angles add to 180°

Tips for using the game

• The math is the shot: every angle problem is drawn on the shot the student just aimed, so x really controls the ball. The right answer plays the shot as aimed; a wrong answer plays the shot that angle would make, so students see their mistake on the table.
• Unlimited tries, growing help: after a miss, the right answer and the related angles are shown, then the same shot comes back with more support each time (the relationship, the equation, the operation, the full solution). There is no hint button.
• Choose the focus: pick a difficulty and any mix of the four skills. Beginner uses clear labels and friendly numbers; Intermediate adds bank shots at the cushion; Challenge adds two-step reasoning and extra lines.
• Three ways to play: Practice (no rules, a new table every shot), classroom 8-ball against the computer (it shows its angle work step by step, and sometimes misses), or two students on one device. In the two-player game a wrong answer still plays out, but the pockets are shut and the turn passes.
• Coins are for math, not pool: each correct answer earns 1 coin, even if the shot misses, for cosmetic cues, tables, ball styles and shot effects.