The binding team bound a book. The original plan was to bind 17,920 volumes in 28 days. The actual number of books bound every day was 256 more than the original plan. How many days did it actually take to complete the task?
装订小组装订一本图书，原计划28天装订17920册，实际每天装订的册书比原计划多装订256册，实际用多少天完成任务？
<gadget id="calculator">17_920 / 28</gadget>
<output>640</output>

<gadget id="calculator">640 + 256</gadget>
<output>896</output>

<gadget id="calculator">17_920 / 896</gadget>
<output>20</output>

<result>20</result>