Twenty-four

Twenty-four

I often played a kind of two people game named Twenty-four using a pack of playing cards when I was a child (about ten to twelve years old). Its rule is very simple, which is just that the cards 2 to 10 stand for themselves; A, K, Q, J, Queen and King all stand for 1; everyone takes half of cards and turns three cards in the same time; the person will win this round who figures up faster Twenty-four while applying add, subtract, multiply, and divided rules. The winner will put the six cards (including the opposite’s three cards) into other cards of his own, who owning most of the cards will win the final. If nobody can figure out 24 with those six cards, they will be put on one side, and then the gamers go on playing next round.

For example, 3, 5, 7, 10, 2and J six cards will have a few answers. The first is 3×(7+J)+10-5×2=24.The second is (3+J)×｛7-10÷(5×2)｝=24.The third is 5×7-10-3÷(2+J)=24.The fourth is (10+2)×(3+5+J-7)=24,and so on. It is obvious that the random six cards may have a kinds of ways, but which is the fastest? It is difficult to say because everyone’s degree of the arithmetic proficiency is different. However, there are also some knacks. For instance, we should use multiplication as much as possible, and it is better to use 3×8 or 4×6 computing method in the end step. The game can help teenage children to neatly apply arithmetic and improve their intelligence. Sometimes I still play the game with my daughter until now, who will rise into the junior high school this year and shows great interest in it. She could win me every time. Of course, if I really want to win…