It takes 9 hours to type a manuscript, 4000 words per hour, to complete. Now it needs to be completed 3 hours ahead of time, how many words should be typed per hour?
打一份书稿，每小时打4000字，要9小时才能完成．现在要提前3小时完成，每小时应打多少字？
<gadget id="calculator">4_000 * 9</gadget>
<output>36_000</output>

<gadget id="calculator">9 - 3</gadget>
<output>6</output>

<gadget id="calculator">36_000 / 6</gadget>
<output>6_000</output>

<result>6_000</result>