On the surface of the earth, the land area is approximately equal to 147.9 million square kilometers, which is 60% less than the water surface area. How many billion square kilometers is the surface area of water?
地球表面，陆地面积约等于1.479亿平方千米，比水面面积少60%．水面面积是多少亿平方千米？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1.479 / (2/5)</gadget>
<output>3.6975</output>

<result>3.6975</result>