To process a batch of parts, A alone can complete it in 8 hours, and B alone can complete it in 10 hours. After A and B cooperate for 2 hours, there are still 440 unprocessed. How many parts are there in this batch?
加工一批零件，甲独做8小时完成，乙独做10小时完成．甲乙合作2小时后，还剩下440个没有加工．这批零件共有多少个？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/8) + (1/10)</gadget>
<output>9/40 = around 0.225</output>

<gadget id="calculator">(9/40) * 2</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 - (9/20)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">440 / (11/20)</gadget>
<output>800</output>

<result>800</result>