There are 3 red balls, 4 white balls, and 5 yellow balls in a box. If you touch any one, how many are the chances of getting a red ball?
盒子里有3个红球、4个白球、5个黄球，任意摸一个，摸到红球的可能是多少
<gadget id="calculator">3 + 4 + 5</gadget>
<output>12</output>

<gadget id="calculator">3 / 12</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>