Put the ten number cards 1, 2, 3, ..., 10 on the table. If you draw any one of them, what is the probability of getting a prime number?
将1、2、3、…、10这十张数字卡片反扣在桌面上．如果从中任意摸一张，那么摸到质数的可能性是多少
<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

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