A 30 cm wire forms a parallelogram, if the length is 9 cm, what is the width in cm?
一根30厘米的铁丝围成一个平行四边形，若长是9厘米，宽是多少厘米．
<gadget id="calculator">30 / 2</gadget>
<output>15</output>

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

<result>6</result>