LESSON 1 Factor Games

Factor 20 and Factor 40 are games about factors. The factors of a number are the whole numbers that can be multiplied together to get the number. For example, 3 and 4 are factors of 12 since 3 4 = 12. All the factors of 12 are 1, 2, 3, 4, 6, and 12.

Factor 20 or Factor 40

The goal is to mark the most factors and earn the most points. This is a game for two players.

Materials

• one Factor 20 Game Board and Score Box or Factor 40 Game Board and Score Box from the Student Activity Book
• one pencil per player
• calculator, optional

Directions

Before Play Begins

• Players will alternate who uses an X and who uses an O for each round. Player X always takes the first turn.

First Turn

• Player X chooses any number except 1 on the game board and draws an “X” on it. Player X writes that number in Column X of the score box. Player X earns that number of points for this turn.
• Player O circles all the factors of Player X's number that are not marked. Player O writes all of those factors in Column O of the score box. Player O earns points equal to the sum of the factors for this turn.

Second Turn

• Player O chooses any unmarked number on the board. (An unmarked number is one that has not yet been circled or marked with an X.) The number must have at least one factor that is unmarked. Player O circles the number and records it in Column O.
• Player X draws an X on all the unmarked factors of that number and records them in Column X.

Play Continues

• Players take turns choosing numbers, marking factors, and recording scores in the score box for each turn.
• Players may choose only numbers that still have unmarked factors.
• The game ends when there are no numbers left with unmarked factors.
• Players total their points at the end of the game. The player with more points wins.