A cuboid can be sawn into exactly 7 identical cubes. How much is the sum of the surface areas of all the cubes increased compared to the original cuboid?
一根长方体木条恰好可以锯成7个完全一样的正方体，所有正方体表面积的和比原来长方体表面积增加了多少．
<gadget id="calculator">7 * 1</gadget>
<output>7</output>

<gadget id="calculator">1 * 1</gadget>
<output>1</output>

<gadget id="calculator">1 * 7</gadget>
<output>7</output>

<gadget id="calculator">7 + 1 + 7</gadget>
<output>15</output>

<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<gadget id="calculator">2 / 30</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 * 1 * 6 * (1/15)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>