The master and apprentice work together to process 156 parts, and the master processes three times as much as the apprentice. How many pieces did the master process?
师徒两人共同加工156零件，师傅加工的是徒弟的3倍．师傅加工了多少个？
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">156 / 4</gadget>
<output>39</output>

<gadget id="calculator">156 - 39</gadget>
<output>117</output>

<result>117</result>