How many 1 in tiles are needed to cover an 18 in by 30 in counter top?

Answer 1

Assuming no gap for grouting the spaces between the tiles, the area is 18 times 30 = 540 square inches, and as each tile measure 1 square inch, the number needed is 540.

However, that's just the answer to the mathematical question. For a real - practical - answer you can assume that the tiles will be spaced approximately one-eighth of an inch apart, which means that 8 tiles will cover 9 linear inches. this means that you will need 16 tiles in one direction and 27 in the other. That is a total of 432 - which is quite a financial saving.