###Human: 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?, ### Assistant: A single layer of each wall requires 5 rows * 20 bricks per row = 100 bricks.
As each wall has a thickness of 2 bricks, he will need 100 bricks * 2 = 200 bricks per wall.
If the complete fence contains four walls, he will require a total of 200*4=800 bricks. 
 So the answer is :  800