There are a batch of parts, Master Li processes 3 parts per hour, and how many parts are left after Master Li processes 6 hours.
一批零件有a个，李师傅每小时加工3个，李师傅加工6小时后，还剩多少个．
<gadget id="calculator">3 * 6</gadget>
<output>18</output>

<result>18</result>