Put the number cards from 1-10 upside down on the table and draw out any one. What is the probability of getting a prime number?
把1-10的数字卡片反扣在桌面上，任意摸出一张，摸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>