To produce a batch of parts, the master can complete it in 9 days alone, and the apprentice can complete it in 15 days. When the master and apprentice work together, the master makes 100 more parts than the apprentice. How many parts are there in total?
生产一批零件，师傅独做9天完成，徒弟独做15天完成，师徒共同完成时，师傅比徒弟多做了100个零件，这批零件共有多少个？
<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/9) + (1/15)</gadget>
<output>8/45 = around 0.177778</output>

<gadget id="calculator">1 / (8/45)</gadget>
<output>45/8 = around 5.625</output>

<gadget id="calculator">(45/8) * (1/9)</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">(45/8) * (1/15)</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(5/8) - (3/8)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">100 / (1/4)</gadget>
<output>400</output>

<result>400</result>