Putting together 7 identical cubes into a large cuboid, its surface area is 84 square centimeters less than the sum of the surface areas of the 7 cubes. What is the surface area of the assembled cuboid in square centimetres?
把7个相同的正方体拼成一个大长方体，它的表面积比7个正方体的表面积的和减少了84平方厘米．拼成后的长方体的表面积为多少平方厘米．
<gadget id="calculator">2 * 6</gadget>
<output>12</output>

<gadget id="calculator">84 / 12</gadget>
<output>7</output>

<gadget id="calculator">7 * 6 * 7</gadget>
<output>294</output>

<gadget id="calculator">294 - 84</gadget>
<output>210</output>

<result>210</result>