A piece of iron wire can just enclose a square with a side length of 10 cm. If it is used to enclose a rectangle, the width is 8 cm, and the length is how many cm.
一根铁丝刚好能围成一个边长为10厘米的正方形，如果用它围成一个长方形，宽是8厘米，长是多少厘米．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">20 - 8</gadget>
<output>12</output>

<result>12</result>