The machinery factory plans to produce 6,120 parts within 16 days, with an average of 420 parts per day in the first 6 days, and an average of 450 parts per day after the innovative technology. Based on this calculation, how many days can this batch of tasks be completed in advance?
机械厂计划在16天内生产零件6120个，前6天平均每天制造420个，革新技术后，平均每天生产了450个，照这样计算，这批任务可提前几天完成？
<gadget id="calculator">420 * 6</gadget>
<output>2_520</output>

<gadget id="calculator">6_120 - 2_520</gadget>
<output>3_600</output>

<gadget id="calculator">3_600 / 450</gadget>
<output>8</output>

<gadget id="calculator">16 - 6 - 8</gadget>
<output>2</output>

<result>2</result>