Cooper is building a brick fence around all four sides of his property.  Each of the four walls of his fence is 20 bricks long, 5 bricks high, and 2 bricks deep.  How many bricks does Cooper need to complete his fence?
A single layer of each wall requires 5 rows * 20 bricks per row = 
<gadget id="calculator">5*20</gadget>
<output>100</output>
100 bricks.
As each wall has a thickness of 2 bricks, he will need 100 bricks * 2 = 
<gadget id="calculator">100*2</gadget>
<output>200</output>
200 bricks per wall.
If the complete fence contains four walls, he will require a total of 200*4=
<gadget id="calculator">200*4</gadget>
<output>800</output>
800 bricks.

<result>800</result>