A toy factory produces a batch of children's toys. In the first week, 1/5 of the plan is completed, and in the second week, 25% of the plan is completed. In the second week, 400 more toys are produced than in the first week. How many toys are there in this batch?
玩具厂生产一批儿童玩具，第一周完成计划的(1/5)，第二周完成计划的25%，第二周比第一周多生产了400个，这批玩具一共有多少个？
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/4) - (1/5)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">400 / (1/20)</gadget>
<output>8_000</output>

<result>8_000</result>