The trademark of liquor reads: Alcohol content is 45%, net content is 50ml, how much water is in this bottle of wine?
白酒的商标上写着：酒精度45%，净含题50ml，这瓶酒含水多少ml．
<gadget id="calculator">45 / 100</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 - (9/20)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">50 * (11/20)</gadget>
<output>55/2 = around 27.5</output>

<result>55/2 = around 27.5</result>