Based on Blackboard's Calculated Formula documentation, when creating variable names:
Variables can be letters, digits (0-9), periods (.), underscores (_) and hyphens (-). Variables cannot contain the letters "e," "i" and "pi" because they are reserved. You cannot reuse variable names. Variables can contain more than one character, such as [ab] or [cd]. All other occurrences of the opening rectangular bracket ("[") should be preceded by the backslash ("\").
However, when I try to create a Calculated Formula question or edit an existing one with variables containing mixed letters and numbers together and advance to the next screen, Blackboard returns to the Question/Answer page and shows the following below. However, I was able to advance to the next page by removing the 0 from the v0 variable name.
Am I misinterpreting how the variable names can be used? Or is this a Blackboard issue?