The side length of a square pond is 15 meters. Xiao Ming walks around it. How many meters does Xiao Ming walk?
一个正方形池塘的边长是15米，小明绕它走了一圈，小明走了多少米．
<gadget id="calculator">15 * 4</gadget>
<output>60</output>

<result>60</result>