Question 794270
Assuming that space (or area) between tiles is to be ingored, you would want to find how many 1/4 x 1/4 square inches is equal to 15x83 square feet.  


Suggestion is, do this all in units of square feet.  You could try all in square inches if you prefer.  Unit conversion is 12 inches = 1 foot.


{{{(15*83/((1/4)(1/4)))*(12*12)}}}   {{{((ft*ft)/(in*in))(in/ft)(in/ft)}}}


Again, that above is converting the inches into feet.  
Ordinary practice is to show the units with the numbers, but this online system breaks that, so here, the units are all shown to the right-side of the number expression.




As a final numeric result, I found 2848680 tiles.  Note above, that the rational expression will be unitless in regard to feet and inches; the expression is a way to count the number of tiles.