The Chrysanthemum Electric Fan Factory needs to process a batch of parts, 261 parts are processed on the first day, and (2/7) of the remaining parts are processed on the second day. In the past two days, half of the total number of parts in this batch were processed. How many parts are there in total?
菊花电扇厂要加工一批零件，第一天加工零件261件，第二天加工余下零件的(2/7)．这两天共加工这批零件总数的一半．则这批零件共有多少个．
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 - (2/7) - (2/7)</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">261 / (3/7)</gadget>
<output>609</output>

<gadget id="calculator">609 + 261</gadget>
<output>870</output>

<result>870</result>