The master and apprentice work together to process a batch of parts, and the plan is to complete them in 16 hours. If the time spent by the master alone is 75% of that of the apprentice, it is known that the apprentice processes 4 fewer parts per hour than the master. How many parts are there in total?
师徒共同加工一批零件，计划16小时完成，如果单独加工师傅所用时间是徒弟的75%，已知徒弟每小时比师傅少加工4个，这批零件共多少个．
<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">4 / (1/4)</gadget>
<output>16</output>

<gadget id="calculator">16 - 4</gadget>
<output>12</output>

<gadget id="calculator">16 + 12</gadget>
<output>28</output>

<gadget id="calculator">16 * 28</gadget>
<output>448</output>

<result>448</result>