Now there is 600ml of a drink with 40% fruit juice, how much water needs to be added to turn it into a drink with 25% fruit juice?
现在有果汁含量为40%的饮料600ml，要把它变成果汁含量为25%的饮料，需要加水多少ml．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">600 * (2/5)</gadget>
<output>240</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">240 / (1/4)</gadget>
<output>960</output>

<gadget id="calculator">960 - 600</gadget>
<output>360</output>

<result>360</result>