The teacher puts 2 red chalks and 3 white chalks in an empty chalk box, and takes out one randomly, what is the probability of getting red chalk?
老师在一个空粉笔盒里放入了2根红粉笔和3根白粉笔，任意拿出一根，拿到红粉笔的可能性是多少．
<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>