A piece of iron wire can be welded into a rectangular parallelepiped frame with a length of 6 cm, a width of 5 cm, and a height of 7 cm (not counting the joints).
一根铁丝正好可以焊成一个长6cm，宽5cm，高7cm的长方体框架(接头处不计)，若用这根铁丝焊成一个最大的正方体框架，那么它的棱长是多少cm．
<gadget id="calculator">7 + 6 + 5</gadget>
<output>18</output>

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

<gadget id="calculator">18 * (1/3)</gadget>
<output>6</output>

<result>6</result>