It depends on what units of measurement are used for the tiles: 18 x 18 inches2, or 18 x 18 cm2, or even 18 x 18 feet2
Two tiles of 16 ft*16 ft will cover 512 square feet.
Each 16 inch tile is 1.78 square feet. You would need 169 tiles, plus some for spoilage.
Tiles that are two feet on a side cover 4 square feet. 378 of them cover 1512 square feet.
256 tiles
76.6 tiles
Two tiles of 16 ft*16 ft will cover 512 square feet.
397
400. That's because there are four six-by-six tiles in each square foot. 4 tiles per square foot X 100 square feet = 400 tiles.
240
4*11=44 44 tiles
192 tiles
Each 16 inch tile is 1.78 square feet. You would need 169 tiles, plus some for spoilage.
864 tiles.144 tiles per square foot.
Tiles that are two feet on a side cover 4 square feet. 378 of them cover 1512 square feet.
500/1.78 = 281 tiles
190
256 tiles