Depends on how many are in each box?
It depends on the units used for measuring the tiles. Obviously, the number of 18 inch x 18 inch tiles required will not be the same as 18 cm x 18 cm tiles. And if there were 18 yard x 18 yard tiles, you would need only 1.
5*6=30*12=360/4=90 tiles
16x16 square feet = 256 square feet, so two tiles will suffice.
If the tiles are 12x12 inches square - you would need... 75 !
The answer depends on the measurement units used for 18x18.
22.2 tiles so buy 23 tiles.
266.666666666 so rounding up 267 tiles.
192 tiles
67 tiles.
start with 38 tiles.
220
10
100 tiles or 96 which is the correct amount
288
118
You'll need 200 18-inch tiles.