Mark 1-10 on each of the 10 cards, place each card upside down on the table, touch any one, what is the probability of getting a composite number
在10张卡片上分别标上1-10，每张卡片都反扣在桌上，任意摸一张，摸到合数的可能性是多少
<gadget id="calculator">5 / 10</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>