Produce a batch of parts and plan to complete the task in 20 days. Since the actual daily production is 150 more than the original plan, the task is completed 5 days ahead of schedule. How many parts are there in this batch? (Solution of column equation)
生产一批零件，计划20天完成任务，由于实际每天比原计划多生产150个，结果提前5天完成任务，这批零件有多少个？(列方程解)
<gadget id="calculator">150 * 20</gadget>
<output>3_000</output>

<gadget id="calculator">150 * 5</gadget>
<output>750</output>

<gadget id="calculator">3_000 - 750</gadget>
<output>2_250</output>

<gadget id="calculator">5 - 20</gadget>
<output>-15</output>

<gadget id="calculator">20 + (-15)</gadget>
<output>5</output>

<gadget id="calculator">2_250 / 5</gadget>
<output>450</output>

<gadget id="calculator">450 * 20</gadget>
<output>9_000</output>

<result>9_000</result>