The washing machine factory originally planned to produce 1,800 washing machines in 40 days, but actually produced 15 more machines per day than the original plan, and actually completed the task a few days earlier than the original plan?
洗衣机厂原计划40天生产1800台洗衣机，实际每天比原计划多生产15台，实际比原计划提前几天完成任务？
<gadget id="calculator">1_800 / 40</gadget>
<output>45</output>

<gadget id="calculator">45 + 15</gadget>
<output>60</output>

<gadget id="calculator">1_800 / 60</gadget>
<output>30</output>

<gadget id="calculator">40 - 30</gadget>
<output>10</output>

<result>10</result>