The perimeter of a rectangle is 6 decimeters, the known length is 18 centimeters, what is its width in centimeters?
一个长方形的周长是6分米，已知长是18厘米，它的宽是多少厘米？
<gadget id="calculator">6 * 10</gadget>
<output>60</output>

<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<gadget id="calculator">30 - 18</gadget>
<output>12</output>

<result>12</result>