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# Tic-Tac-Toe Sums

This game is a great way to practice and build fluency with the addends 0 – 12. As students develop new strategies they will begin to use subtraction. Encourage students to discuss, write about or illustrate their strategies after they have played. You can also ask students to explain why they are choosing their addend and to justify the sum of their addends during play.

• Player X and Player O each select one of the numbers, 0 – 12 at the bottom of the page and places one of the markers on that addend.
• Player X may move only one of the two addend markers to a different addend. Player X then places a marker on the grid covering the sum of the two addends.
• Player O may move only one addend marker at the bottom of the page, 0 – 12. Player O makes a new sum and covers it on the grid. The markers can be placed on the same numbers, 0 – 12. For example, two markers on 12 would be 12 + 12 = 24 and the player would cover 24 on the grid.
• Players alternate moving one addend marker at a time and continue placing their markers until a player has marked four sums in a row. After the game players should discuss their strategies.

## Materials

• Two markers for the bottom row of addends (for example, paper clips)
• Two sets of different markers for each player to cover each sum (for example, pennies and nickels)
• Tic-Tac-Toe Sums Game Sheets

## Reference

From Helping with Math at Home: More Ideas for Parents. 2006. Portsmouth, NH: Heinemann.