The two masters and apprentices had to produce 2,100 parts, which were planned to be completed in 10 days, but actually produced 35 fewer parts per day. How many days did it actually take to complete this task?
师徒二人要生产2100个零件，计划10天完成，实际每天少生产了35个，完成这项任务实际用了多少天？
<gadget id="calculator">2_100 / 10</gadget>
<output>210</output>

<gadget id="calculator">210 - 35</gadget>
<output>175</output>

<gadget id="calculator">2_100 / 175</gadget>
<output>12</output>

<result>12</result>