There are 8 white ping-pong balls and 12 yellow ping-pong balls of the same size in a cloth bag. If you touch any one of them, what is the probability of getting a white ping-pong ball?
一个布袋中有大小一样的白色乒乓球8个，黄色乒乓球12个，从中任意摸一个，摸到白色乒乓球的可能性是多少．
<gadget id="calculator">8 + 12</gadget>
<output>20</output>

<gadget id="calculator">8 / 20</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>