A factory plans to produce a batch of parts, the first completion of the plan (1/2), the second completion of the plan (3/7), the third completion of 450, the result exceeds the plan (1/4), the plan How many parts are produced?
某工厂计划生产一批零件，第一次完成计划的(1/2)，第二次完成计划的(3/7)，第三次完成450个，结果超过计划的(1/4)，计划生产零件多少个？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(1/4) - (1/2) - (3/7)</gadget>
<output>-19/28 = around -0.678571</output>

<gadget id="calculator">1 + (-19/28)</gadget>
<output>9/28 = around 0.321429</output>

<gadget id="calculator">450 / (9/28)</gadget>
<output>1_400</output>

<result>1_400</result>