There are 10 small balls in a bag, and each small ball is marked with 10 numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and a small ball is taken out, marked with What is the probability of a prime number.
一个袋子中装有10个小球，每个小球上分别标有0，1，2，3，4，5，6，7，8，9这10个数字，从中取出一个小球，标有质数的可能性为多少．
<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

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