Use a piece of rope 60 meters long to surround a square nursery field with a side length of 12 meters. How many meters are left?
用一段长60米的绳子，将一块边长是12米的正方形苗圃地围一周，还剩多少米？
<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<gadget id="calculator">60 - 48</gadget>
<output>12</output>

<result>12</result>