Teacher Li can type 320 characters in 4 minutes, how many characters can she type in half an hour?
李老师4分钟打320个字，请问半小时她能打多少个字？
<gadget id="calculator">320 / 4</gadget>
<output>80</output>

<gadget id="calculator">80 * 30</gadget>
<output>2_400</output>

<result>2_400</result>