piece of wire is 85 cm long. After making a square frame with a side length of 18 cm, how many cm is left?
一段铁丝长85厘米，做了一个边长是18厘米的正方形框子后，还剩多少厘米？
<gadget id="calculator">18 * 4</gadget>
<output>72</output>

<gadget id="calculator">85 - 72</gadget>
<output>13</output>

<result>13</result>