A rope is 12 meters long. Now it is 0.56 meters short of winding 4 times around a big tree. Find the diameter of the big tree.
一根绳子长12米，现在一棵大树上绕4周还差0.56米，求这棵大树的直径．
<gadget id="calculator">12 + 0.56</gadget>
<output>12.56</output>

<gadget id="calculator">12.56 / 4 / 3.14</gadget>
<output>1</output>

<result>1</result>