Last date for submission of paper: unknown; Contact person: unknown; Basic strategic thinking: how to choose the best card considering their own cards only which involves predicting each of the four cards' effects and choosing between these (see Figure 5A-D for examples) 5) Advanced strategic thinking: how to choose the best card considering both players' cards and predicting two steps ahead. Normally this means considering and discriminating between 16 alternatives that are two arithmetic computations ahead