2.  Option 1 › Separate entries and hide fields › Hide columns or use separate spreadsheets  Option 2 › Build them up in pieces › Use parentheses if you can’t remember precedence  Option1, followed by option 2

3.  Input errors › Will look at case sensitive and extra blanks when we look at strings › For now, worry about content only  Errors in computation › USUALLY from bad input › BUT sometimes other cases

4. LL

5.  Do not want Excel error messages But do not want to ignore errors Use built-in functions to be more friendly  Error checking makes expressions complex But do not want to require perfect input Options: › Check and convert › Hide columns or use separate spreadsheets

6.  Types of errors Types of errors  IFERROR Simple computation: just use it Complex computation: hide column  Translating their errors ERROR.TYPE CHOOSE =CHOOSE(ERROR.TYPE(C2),"NULL","DIV","VAL","REF", "NAME")