There are 1 red ball, 1 yellow ball, and 1 green ball in a box. If you touch 1 ball at random, what is the probability of getting a red ball?
一个盒子里放有红球、黄球、绿球各1个，任意摸1个，摸到红球的可能性是多少．
<gadget id="calculator">1 + 1 + 1</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<result>1/3 = around 0.333333</result>