There are 5 pencils, 2 ballpoint pens and 3 pens in the pen box, if one is chosen at random, what is the probability that it is a pen
笔盒里有5支铅笔、2支圆珠笔和3支钢笔，任取一支，是钢笔的可能性为多少
<gadget id="calculator">5 + 2 + 3</gadget>
<output>10</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<result>3/10 = around 0.3</result>