Arrange 8 small squares whose side length is 1 decimeter in a row to form a large rectangle. What is the perimeter of this large rectangle in decimeters?
把8个边长是1分米的小正方形，排成一排拼成一个大长方形，这个大长方形的周长是多少分米．
<gadget id="calculator">1 * 8</gadget>
<output>8</output>

<gadget id="calculator">8 + 1</gadget>
<output>9</output>

<gadget id="calculator">9 * 2</gadget>
<output>18</output>

<result>18</result>