If a rope forms a square with a side length of 6 meters, there is still a difference of 4 meters. How long is the rope in meters?
一根绳子，如果围成边长6米的正方形，还差4米，这根绳子长多少米？
<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">24 - 4</gadget>
<output>20</output>

<result>20</result>