1. Let your child draw a standard nine-square tic-tac-toe grid on the sheet of white paper using the black marker.
2. Have your kid use the left side of the following chart and the black marker to fill each of the squares in the grid randomly. This chart can also be the gamekeeper's cheat sheet during game play.
1 millimeter = 0.001 meter
1 centimeter = 0.01 meter
1 decimeter = 0.1 meter
1 decameter = 10 meters
1 hectometer = 100 meters
1 kilometer = 1000 meters
You'll want to fill it out in such a way that each square contains a single figure. For example, you could write millimeter in the top left square, decameter in the top center square, centimeter in the top right square, 100 meters in the center square and so on. Try to be as random as possible.
3. To play the game, your child and her friend should decide who will go first.
4. The child who goes first should pick a random square and then try and convert it to or from meters. For example, if she picks a square that contains the term hectometer, she needs to correctly guess how many meters a hectometer equals.
5. If she guesses correctly, she gets to write an X or an O in the square.
6. Then, the next child should take his turn.
7. The game continues until someone gets three squares in a row. Whoever gets three squares in a row first—wins!
8. The best part is that this game could easily be converted to other metric measurements (liters, grams) instead of meters for added replayability.