batch of parts was planned to produce 42 sets per day, and it was completed in 20 days. In fact, 14 more sets were produced per day. As a result, the task was completed a few days ahead of schedule. (Use proportional solution)
一批零件计划每天生产42套，20天完成，实际每天多生产14套，结果提前几天就完成了任务，(用比例解)
<gadget id="calculator">42 * 20</gadget>
<output>840</output>

<gadget id="calculator">14 * 20</gadget>
<output>280</output>

<gadget id="calculator">280 - 840</gadget>
<output>-560</output>

<gadget id="calculator">840 + (-560)</gadget>
<output>280</output>

<gadget id="calculator">42 + 14</gadget>
<output>56</output>

<gadget id="calculator">280 / 56</gadget>
<output>5</output>

<result>5</result>