RASTER MINUS FUNCTION NOT WORKING AS EXPECTED

[StevenHill1]

ArcMap 9.3 Spatial Analyst Math function Minus.  I have two ASCII rasters with identical extent and cell size representing mean annual temperatures.  I want to difference the two rasters to produce an output raster with the same extent and cell size.  However when I use the tool I get a raster with only 1 row and one column.  I also get an attribute table with three rows and fields of VALUE and COUNT.  What am I doing wrong?  

[DanPatterson_Retired]

convert the ascii files first to *.tif format and try again, otherwise just try subtracting a constant value from them to see if you get an appropriate output

ASCII to Raster—Conversion toolbox | ArcGIS Desktop 

Minus—Help | ArcGIS Desktop