Uncle worker divides a rectangular plank with a length of 12 decimeters and a width of 3 decimeters into 2 pieces, puts it together into a square guide sign, and nails a circle of wooden strips to the guide sign to fix it. You know how long the plank will be article?
工人叔叔把一块长12分米，宽3分米的长方形木板平均分成2块后，拼成一个正方形的指路牌，又给这个指路牌钉了一圈木条固定，你知道需要多长的木条吗？
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<result>24</result>