Three teams in a certain workshop made a batch of parts. The first team made 2/7 of the total number, the second team made 600 pieces, and the third team made half of the sum of the first and second teams. How many parts are there in this batch?
某车间三个小组共做一批零件，第一小组做了总数的(2/7)，第二小组做了600个，第三小组做的个数是一、二两个小组总和的一半，这批零件共有多少个？
<gadget id="calculator">600 / 2</gadget>
<output>300</output>

<gadget id="calculator">600 + 300</gadget>
<output>900</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(2/7) * (1/2)</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 - (2/7) - (1/7)</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">900 / (4/7)</gadget>
<output>1_575</output>

<result>1_575</result>