Among the seven cards 54, 7, 5, 56, 6, 45, and 9, A, B, and C each took two cards, and then calculated by division. A said, "The quotient is 6." B said, "The quotient is 9." C said, "The quotient is 8." Their calculations were correct. So, how much is written on the remaining card.
在54、7、5、56、6、45、9这七张卡片中，甲乙丙三人分别各取了两张，然后用除法算．甲说"商是6．"乙说："商是9．"丙说："商是8．"他们的计算都正确．那么，剩下的一张卡上写有多少．
<gadget id="calculator">54 / 9</gadget>
<output>6</output>

<result>6</result>