Using five cards of 5, 6, 7, 8, and 9, what is the probability that any five-digit number formed is an odd number?
用5、6、7、8、9五张卡片，任意组成的五位数是单数的可能性是多少．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>