Since 12" by 12" is one foot by one foot or one square foot, 1237 of these tiles will feet in 1237 square feet.
650
1540
Since a 12" x 12" tile is exactly one square foot, the answer should be obvious.
If the tiles are 12 inches square... 8352 tiles ! However if they're 12 feet square... 58 tiles
Since a 12x12 tile is one square foot, then 38 12x12 tiles will cover 38 square feet.
190
80 if the tiles are 12x12 - 12x12 is one square foot covering 80 you would need 80 tiles
14
68
375
Since 12" by 12" is one foot by one foot or one square foot, 1237 of these tiles will feet in 1237 square feet.
1540
650
Well if 12x12 is one square foot and you have 44 you need to cover figure 10% for breakage (5 tiles) it looks like 50 tiles will do ya
If the tiles are 12x12 inches square - you would need... 75 !
If you're talking floor tiles as opposed to wall tiles and by 12x12 you mean they are 12 inches square, then the answer is 300. Because each tile is one square foot and a 15'x20' room is 300 square feet. Simple, eh?