There are 5 red balls, 3 yellow balls and 2 white balls in a bag. Each time a ball is touched, what is the probability that it is a red ball?
袋子里有红球5个、黄球3个、白球2个．每次摸1个球，是红球的可能性是多少．
<gadget id="calculator">5 + 3 + 2</gadget>
<output>10</output>

<gadget id="calculator">5 / 10</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>