There are 4 red balls and 4 white balls in the box. If one is drawn randomly, what is the probability of getting a red ball?
盒中有红色、白色的球各4个，任意摸出一个，摸到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>