Put 20 cards with 1 to 20 written on them in a paper bag, draw one at random, what is the probability of finding a prime number
把分别写有1～20的20张卡片放人纸袋中，任意摸出一张，摸出素数的可能性是多少
<gadget id="calculator">8 / 20</gadget>
<output>2/5 = around 0.4</output>

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