The binding workshop plans to bind 9,600 books. The original plan was to bind 480 copies per day, but due to improved technology, the actual number of bindings was 120 more per day than planned, so that the task can be completed a few days earlier?
装订车间计划装订9600本书．原计划每天装订480本，由于改进了技术，实际每天比计划多装订120本，这样可以提前几天完成任务？
<gadget id="calculator">9_600 / 480</gadget>
<output>20</output>

<gadget id="calculator">480 + 120</gadget>
<output>600</output>

<gadget id="calculator">9_600 / 600</gadget>
<output>16</output>

<gadget id="calculator">20 - 16</gadget>
<output>4</output>

<result>4</result>