It is planned to process a batch of children's clothing, but the planned (5/8) is completed in the first week, and 400 sets are processed in the second week, which is more than planned (1/4). How many sets of children's clothing does the garment factory plan to process?
计划加工一批童装，第一周完成了计划的(5/8)，第二周加工了400套，结果超过计划的(1/4)，服装厂计划加工多少套童装？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">(1/4) - (5/8)</gadget>
<output>-3/8 = around -0.375</output>

<gadget id="calculator">1 + (-3/8)</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">400 / (5/8)</gadget>
<output>640</output>

<result>640</result>