For a batch of parts, 120 parts are processed first, and the rest (2/5) are processed. At this time, the number of processed parts is equal to the number of unprocessed parts. How many parts are there in total?
一批零件，先加工120个，又加工余下的(2/5)，这时已加工的零件个数与未加工的零件个数相等，这批零件共多少个？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(1/2) / (3/5)</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">1 - (5/6)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">120 / (1/6)</gadget>
<output>720</output>

<result>720</result>