Ten number cards are written as ten numbers from 1 to 10. What is the probability of drawing a prime number?
十张数字卡片写成1～10十个数，抽到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>