There are red, yellow and white balls in a box, all of which are the same except for the color. The ratio of red, yellow and white is 3:2:1. If you touch any one of them, what is the probability of getting a yellow ball?
盒内有红、黄、白三种颜色的球，除颜色外，其它都相同．红、黄、白三种比是3：2：1，从中任意摸一个，摸到黄球的可能性是多少．
<gadget id="calculator">3 + 2 + 1</gadget>
<output>6</output>

<gadget id="calculator">2 / 6</gadget>
<output>1/3 = around 0.333333</output>

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