There are 4 red balls, 4 white balls and 4 yellow balls in a sealed opaque bag. Lulu reaches out and touches a ball at random. What is the probability of touching a red ball?
在一个密封的不透明的袋子里装了红球、白球、黄球各4个，露露伸手任意摸一个球，摸到红球的可能性是多少
<gadget id="calculator">4 + 4 + 4</gadget>
<output>12</output>

<gadget id="calculator">4 / 12</gadget>
<output>1/3 = around 0.333333</output>

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