There is 280mL of water in a cup, the height of the cup is 18cm, and the depth of water is 12cm. How much water can it hold?
一个水杯，杯中有280mL水，杯高18cm，水深12cm，还可装多少水？
<gadget id="calculator">280 / 12</gadget>
<output>70/3 = around 23.333333</output>

<gadget id="calculator">1 / 18</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">(70/3) / (1/18)</gadget>
<output>420</output>

<gadget id="calculator">420 - 280</gadget>
<output>140</output>

<result>140</result>