There are 3 red balls, 3 blue balls, and 6 yellow balls in a box. What is the probability of touching the yellow ball?
盒子里放着3个红球，3个蓝球，6个黄球，摸到黄球的可能性是多少．
<gadget id="calculator">3 + 3 + 6</gadget>
<output>12</output>

<gadget id="calculator">6 / 12</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>