Dongdong walks twice along a square lotus pond with a side length of 10 meters, how many decimeters in total.
东东沿边长为10米的正方形荷花池走两圈，一共走多少分米．
<gadget id="calculator">4 * 10 * 2 * 10</gadget>
<output>800</output>

<result>800</result>