How to subtract Fields.Items.Value from otherFields.Items.Value

Using Classic ASP, VBScript, & SQL. I created two record sets CY & LY which provide current year results (number) and last year results (number). I want to subtract CY - LY and display the results on a Web form only for reference and not for input and I get a mismatch error. my syntax is:

<%=(CY.Fields.Item("Result").Value) - (LY.Fields.Item("Result").Value)%>

Any guidance or help with this is greatly appreciated.