There are three cards with 5, 6, and 7 written on them. Xiaohong and Xiaoming use these three cards to place different three-digit numbers in turn. If the three-digit numbers are odd, Xiaohong wins, otherwise Xiaoming wins. What is the probability that Xiaohong wins.
有三张卡片，上面分别写着5、6、7．小红和小明用这三张卡片轮流摆不同的三位数，如果摆出的三位数是奇数就是小红赢，否则小明赢．小红赢的可能性是多少．
<gadget id="calculator">3 * 2 * 1</gadget>
<output>6</output>

<gadget id="calculator">4 / 6</gadget>
<output>2/3 = around 0.666667</output>

<result>2/3 = around 0.666667</result>