To process a batch of parts, the two masters and apprentices cooperate, and it can be completed in 12 days. Now the master works for one day first, and then the apprentice continues to work for 3 days. At this time, the remaining parts (17/20) are not completed. It is known that the master processes 60 more parts than the apprentice every day. How many parts are left unprocessed in this batch?
加工一批零件，师徒二人合作，12天可以完成．现在先由师傅干一天，然后徒弟接着工作了3天，这时还剩下这批零件的(17/20)没有完成．已知师傅每天比徒弟多加工60个，这批零件还有多少个没有加工？
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">17 / 20</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">(1/12) * 1</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 - (17/20) - (1/12)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">(1/15) / 2</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/12) - (1/30) - (1/30)</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">60 / (1/60)</gadget>
<output>3_600</output>

<gadget id="calculator">3_600 * (17/20)</gadget>
<output>3_060</output>

<result>3_060</result>