There is a lake in the park, and the rest are green spaces, buildings and roads. It is known that the park area is 1 (2/5) square kilometers, and the green area is (2/3) of the park. The total area of buildings and roads It is (1/18) of the park area. Find the ratio of the area of the lake to the area of the green area.
公园内有一个湖泊，其余为绿地、建筑物和道路，已知公园面积为1(2/5)平方千米，绿地面积为公园的(2/3)，建筑物和道路的占地总面积是公园面积的(1/18)．求湖泊的面积与绿地面积的比值．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 * (2/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

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

<gadget id="calculator">1 - (2/3) - (1/18)</gadget>
<output>5/18 = around 0.277778</output>

<gadget id="calculator">(2/5) * (2/3)</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">(5/18) / (4/15)</gadget>
<output>25/24 = around 1.041667</output>

<gadget id="calculator">(2/5) * (25/24)</gadget>
<output>5/12 = around 0.416667</output>

<result>5/12 = around 0.416667</result>