There are 4 red balls, 4 white balls and 4 yellow balls in a bag, what is the probability of drawing a red ball from the bag
袋子中有红球、白球、黄球各4个，从袋子中摸出一个红球的可能性为多少
<gadget id="calculator">4 * 3</gadget>
<output>12</output>

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

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