A rectangle has a circumference of 60 cm and a length of 18 cm. What is the width in cm?
一个长方形周长60厘米，长18厘米，宽是多少厘米？
<gadget id="calculator">60 / 2</gadget>
<output>30</output>

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

<result>12</result>