An object falls from the sky, it falls 4.9 meters in the first second, then it falls 9.8 meters per second, after 4 seconds, what is the original distance of the object from the ground?
一个物体从空中落下，第一秒落4.9米，以后每秒多落下9.8米，经过4秒钟落下，物体原来离地面是多少米．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">3 * 9.8</gadget>
<output>29.4</output>

<gadget id="calculator">4.9 + 29.4</gadget>
<output>34.3</output>

<gadget id="calculator">4.9 + 34.3</gadget>
<output>39.2</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">39.2 * 2</gadget>
<output>78.4</output>

<result>78.4</result>