This two-sided wooden game board combines strategic play with math practice (manipulating numerals to produce desired totals). In Knock-Out!, the simpler game with a circle of numbers from 1 to 18, players roll three dice and add the numbers together. They then put a marble of their color next to that number, or several marbles next to any combination of numbers that equals the total. A subsequent player whose dice roll earns the right to put a marble adjacent to a previous player's number, knocks out the earlier marble. Only when a player has a marble of his or her own color on both sides of a number, does he "capture" that number and earn a point. The strategy is to decide how best to manipulate the numbers in order to place marbles where they earn points.

The more advanced game, Muggins!, has 36 numbers with adjacent spaces for marbles. Players again roll three dice, but now they may add, subtract, multiply, and/or divide in order to determine the number where their marble will be placed. In deciding which of many options to select, particularly early in the game, players must keep in mind that higher scores are earned for longer "runs" of adjacent same-color marbles. This can be played as a solitaire game with the goal of filling in all the spaces with the minimal number of dice rolls; 36 would be a perfect score.