A 72 cm long iron wire can be welded into a rectangular parallelepiped frame. The frame is 9 cm long, 6 cm wide, and how many centimeters high.
用一根72厘米长的铁丝，恰好可以焊成一个长方体框架，框架长9厘米，宽6厘米，高多少厘米．
<gadget id="calculator">72 / 4</gadget>
<output>18</output>

<gadget id="calculator">9 + 6</gadget>
<output>15</output>

<gadget id="calculator">18 - 15</gadget>
<output>3</output>

<result>3</result>