Uncle Wang picked a batch of fresh red dates with a water content of 75%, and dried these fresh red dates into 400 kilograms of red dates with a water content of 10%. How many kilograms are there in this batch of fresh red dates?
王大爷采摘了一批含水量为75%的鲜红枣，把这批鲜红枣晒成400千克，含水10%的红枣，原来这批鲜红枣有多少千克？
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">400 * (9/10)</gadget>
<output>360</output>

<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">360 / (1/4)</gadget>
<output>1_440</output>

<result>1_440</result>