To process a batch of parts, it takes 30 hours for A alone, and 20 hours for B to complete it. Now the two work together. When it is completed, A will make 36 fewer parts than B. How many parts are there in total?
加工一批零件，单独做甲要30小时，乙要20小时可以完成，二人现在合做，完成时，甲比乙少做36个零件，这批零件共有多少个？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/20) - (1/30)</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">(1/30) + (1/20)</gadget>
<output>1/12 = around 0.083333</output>

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

<gadget id="calculator">(1/60) * 12</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">36 / (1/5)</gadget>
<output>180</output>

<result>180</result>