If you put together 5 squares with a side length of 3 cm to form a rectangle, what is the perimeter of the rectangle?
把5个边长为3厘米的正方形拼成一个长方形，这个长方形的周长是多少？
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">15 + 3</gadget>
<output>18</output>

<gadget id="calculator">18 * 2</gadget>
<output>36</output>

<result>36</result>