It may depend on which version of Paradox, but certainly, in DOS, you are limited to the amount of Math functions that can be used in a query (eg INT, ROUND can not be used).
So I can't come up with a method of doing this in a query. I tend to use a SCAN loop and do each record in turn.
SCAN
[Number Field] = INT([Number Field]+.5)
ENDSCAN
or a more complex text if you want.
7.2+.5 = 7.7 = 7
7.5+.5 = 8.0 = 8
8.0+.5 = 8.5 = 8
Phil