There are 4 red balls and 4 green balls in a bag. If a ball is drawn at random, what is the probability of drawing a red ball?
袋子里装有4个红球和4个绿球，任意摸出一个球，摸出红球的可能性是多少
<gadget id="calculator">4 + 4</gadget>
<output>8</output>

<gadget id="calculator">4 / 8</gadget>
<output>1/2 = around 0.5</output>

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