If a square with a side length of 10 cm is removed from each of the four corners of a small square with a side length of 3 cm, what is the perimeter of the remaining figure in cm?
一个边长为10厘米的正方形，在四个角上各去掉一个边长为3厘米的小正方形，那么剩下的图形周长是多少厘米．
<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<result>40</result>