A batch of parts, the master alone takes 5 hours to complete, and the apprentice alone takes 8 hours to complete. When two people cooperate to complete the task, the master makes 42 more parts than the apprentice. How many parts are in this batch?
一批零件，师傅独做需5时完成，徒弟独做需8时完成．两人合作完成任务时，师傅比徒弟多做42个零件．这批零件共多少个？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/5) + (1/8)</gadget>
<output>13/40 = around 0.325</output>

<gadget id="calculator">1 / (13/40)</gadget>
<output>40/13 = around 3.076923</output>

<gadget id="calculator">(40/13) * (1/5)</gadget>
<output>8/13 = around 0.615385</output>

<gadget id="calculator">(40/13) * (1/8)</gadget>
<output>5/13 = around 0.384615</output>

<gadget id="calculator">(8/13) - (5/13)</gadget>
<output>3/13 = around 0.230769</output>

<gadget id="calculator">42 / (3/13)</gadget>
<output>182</output>

<result>182</result>