There are 3 red balls and 7 yellow balls in a box. If you touch a ball at random in the box, what is the probability of drawing a red ball?
一个盒子里装了3个红球，7个黄球．在盒子里任意摸一个球，摸出红球的可能性是多少
<gadget id="calculator">3 + 7</gadget>
<output>10</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<result>3/10 = around 0.3</result>