The earth's surface area is 510 million square kilometers, of which the land area is 149 million square kilometers, and the rest is the ocean area. How many billion square kilometers more is the ocean area than the land area?
地球表面积是5.1亿平方千米，其中陆地面积是1.49亿平方千米，其余是海洋面积，海洋面积比陆地面积多多少亿平方千米？
<gadget id="calculator">5.1 - 1.49 - 1.49</gadget>
<output>2.12</output>

<result>2.12</result>