Set up a game
Score
Check board marks squares whose number does not belong there, without saying what the right number is. Arrow keys move around the board; Enter picks a square.
How to play
- Each player has a color. Take turns.
- On your turn, pick any blank square and write the number that belongs there. On paper, use your own colored pencil.
- Four of your squares in a row, a column or a diagonal is a tic-tac-toe, worth 1 point. Keep score with tally marks. With three players, three in a row scores.
- A square can be part of only one tic-tac-toe.
- Numbers that are printed on the board before you start belong to nobody and never count.
- Play until the board is full. Then check every number: a tic-tac-toe with a wrong number in it is crossed out. Most points wins.
For parents and teachers
Wrong numbers are not pointed out when they are written. As more of the board fills in, players notice that something does not fit and have to work out which square is wrong. A good question to ask: How will you know if a number is in the wrong place?
Other questions: What is one square down from 46? One square to the right? How did you find 83 without counting from 1? Where should the next player go, and why?
Easier: the Helper board, or play with the printed hundreds chart on the table. Harder: Scattered clues (no 1 or 100), 1 to 120, decimals or the times table.
Print it
Boards: 1 to 100 (with 1 and 100 shown), 1 to 120, a Helper board, Scattered clues, decimals 0.1 to 10.0 and the times table to 10 × 10.
Game idea: Number Grid Tic-Tac-Toe by Joe Schwartz, a math teacher, who invented it while working with a second grader and shared it on his blog, Exit 10A (January 2016), inviting teachers to share it with credit. The 1 to 120 grid, three players with three in a row, scattered clues, decimals and the times table all come from his post and his readers. This page and the boards are School Launch's own design.