There are 3 black beads, 4 yellow beads, and 5 red beads of the same size in a bag. If you touch any one, what is the probability of getting the yellow beads?
袋中有大小相同的黑珠3颗，黄珠4颗，红珠5颗，任意摸一颗，摸到黄珠的可能性是多少．
<gadget id="calculator">3 + 4 + 5</gadget>
<output>12</output>

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

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