A cuboid becomes a cube if its height increases by 3 cm, and its surface area increases by 84 cm2. What is the volume of this cuboid?
一个长方体，如果高增加3厘米就成为一个正方体，而且表面积要增加84平方厘米．原来这个长方体的体积是多少？
<gadget id="calculator">84 / 3</gadget>
<output>28</output>

<gadget id="calculator">28 / 4</gadget>
<output>7</output>

<gadget id="calculator">7 - 3</gadget>
<output>4</output>

<gadget id="calculator">7 * 7 * 4</gadget>
<output>196</output>

<result>196</result>