It is planned to produce a batch of parts, A alone needs 8 hours to complete, B alone needs 10 hours to complete, and A and B cooperate to produce 6 hours, the result is 490 more parts than calculated. How many parts do you plan to produce?
计划生产一批零件，甲单独做需8小时完成，乙单独做需要10小时完成，甲乙两人合作生产6小时，结果比计算多生产490个零件．计划生产零件多少个？
<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) * 6</gadget>
<output>27/20 = around 1.35</output>

<gadget id="calculator">(27/20) - 1</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">490 / (7/20)</gadget>
<output>1_400</output>

<result>1_400</result>