4 workers can produce 108 parts in 3 hours, now we need to produce 504 parts in 8 hours, how many more workers are needed?
4名工人3小时可以生产零件108个，现在要在8小时内生产504个零件，需增加工人多少名．
<gadget id="calculator">108 / 3 / 4</gadget>
<output>9</output>

<gadget id="calculator">504 / 8 / 9</gadget>
<output>7</output>

<gadget id="calculator">7 - 4</gadget>
<output>3</output>

<result>3</result>