Uncle Wang has to process 900 parts, and the plan is to finish it in 20 days. Actually, he makes 5 more parts every day than the original plan. How many days earlier?
王叔叔要加工900个零件，计划20天完成，实际每天比原计划多做了5个，实际提前几天完成？
<gadget id="calculator">900 / 20</gadget>
<output>45</output>

<gadget id="calculator">45 + 5</gadget>
<output>50</output>

<gadget id="calculator">900 / 50</gadget>
<output>18</output>

<gadget id="calculator">20 - 18</gadget>
<output>2</output>

<result>2</result>