I do have a quantity column (its called Amount in the DB)

anyway, I just thought of something as I began to work on this feature of the program. I cant multiply a string.

Acceptable values for the Amount column are things like 1 or 0.25 or 1/8th. Right now the column is a nchar(10) in SQL Server.

What datatype could I change it to if I want to multiply 1/8th by say 5 and successfully get 5/8ths or multiply 0.25 by 5 and get 1 and 1/4th?