The sum of the sides of a cuboid and a cube are equal. It is known that the length, width and height of a cuboid are 6dm, 5dm and 4dm respectively, then what is the edge length of the cube in dm?
一个长方体和一个正方体的棱长总和相等．已知长方体的长、宽、高分别是6dm、5dm、4dm，那么正方体的棱长是多少dm．
<gadget id="calculator">6 + 5 + 4</gadget>
<output>15</output>

<gadget id="calculator">4 / 12</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">15 * (1/3)</gadget>
<output>5</output>

<result>5</result>