It's almost certainly a integer / conversion problem: if I use DECIMAL values throughout, I get what I expect.
DECLARE @A DECIMAL(7,2) = 3990
DECLARE @B DECIMAL(7,2) = 460
DECLARE @C DECIMAL(7,2) = 95
DECLARE @VAL DECIMAL(7,2) = (@A - @B) / @C
DECLARE @IA INTEGER = 3990
DECLARE @IB INTEGER = 460
DECLARE @IC INTEGER = 95
DECLARE @IVAL DECIMAL(7,2) = (@IA - @IB) / @IC
SELECT (@A - @B) / @C, (@IA - @IB) / @IC, @VAL, @IVAL, (3990 - 460) / 95
(No column name) (No column name) (No column name) (No column name)
(No column name)
37.1578947368 37 37.16 37.00 37
So check your value types! At a guess, you are using the wrong column type, but we can't check your DB - we don;t have any access to it.