Processing a batch of parts, A alone takes 6 hours to complete, B alone takes 8 hours to complete, and A and B work together for 3 hours, a total of 560 parts are processed. How many parts are there in this batch?
加工一批零件，甲单独做要6小时完成，乙单独做要8小时完成，甲、乙两人合做3小时，一共加工零件560个．这批零件共有多少个？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/6) + (1/8)</gadget>
<output>7/24 = around 0.291667</output>

<gadget id="calculator">(7/24) * 3</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">560 / (7/8)</gadget>
<output>640</output>

<result>640</result>