Manufacture a batch of machine parts, plan to manufacture 200 per day, complete in 15 days, actually produce 50 more per day, how many days earlier than planned?
制造一批机器零件，计划每天制造200个，15天完成，实际每天多生产50个，比计划提前几天完成？
<gadget id="calculator">200 * 15</gadget>
<output>3_000</output>

<gadget id="calculator">200 + 50</gadget>
<output>250</output>

<gadget id="calculator">3_000 / 250</gadget>
<output>12</output>

<gadget id="calculator">15 - 12</gadget>
<output>3</output>

<result>3</result>