How many is this? Practice number value recognition between 0 and 20 using this interactive activity idea. It's all here for your easy use: cut and laminate the twenty-one individual cards, each labeled numerically 0-20. Also cut out the markers, both x and o. A game is suggested to make counting more fun, during which teams compete to get the correct number of markers on the board. Consider making two or more sets of boards for this game to go smoothly as a team activity.