What is the probability that a card drawn at random from ten cards with numbers 1 to 10 is exactly a prime number?
在写有1到10的十张卡片中随机抽取一张卡片正好是素数的可能性是多少．
<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>