A rope is 1 meter long. After using this rope to form a square with a side length of 18 centimeters, how many centimeters are left on the rope?
一根绳子长1米，用这根绳子围成一个边长18厘米的正方形后，这根绳子还剩下多少厘米．
<gadget id="calculator">1 * 100</gadget>
<output>100</output>

<gadget id="calculator">18 * 4</gadget>
<output>72</output>

<gadget id="calculator">100 - 72</gadget>
<output>28</output>

<result>28</result>