Pour 30L of water into a fish tank with a length of 5dm, a width of 4dm, and a height of 3.2dm. How many decimeters is the water surface from the mouth of the fish tank?
将30L水倒入长5dm，宽4dm，高3.2dm的鱼缸内，水面离鱼缸口多少分米？
<gadget id="calculator">30 / 5 / 4</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">3.2 - (3/2)</gadget>
<output>1.7</output>

<result>1.7</result>