There are 2 black balls and 3 white balls of the same shape and size in a pocket, and a ball is randomly drawn from it, what is the probability of getting a black ball?
口袋里装有形状、大小一样的2个黑球和3个白球，从中任意摸出一个球，摸到黑球的可能性是多少．
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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