 CHOOSE › Index and list of options › Example: alternative to grade translation

 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

 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 and only change at last step

 ISERROR and ISERR Checks if a cell has an error  IFERROR Simple form of IF(ISERROR,,) Simple computation: just use it Complex computation: hide column  Translating their errors ERROR.TYPE CHOOSE =CHOOSE(ERROR.TYPE(C2),"NULL","DIV","VAL","REF", "NAME")

 Conditional Formatting  Cell Styles are short hands  Alignment options  Page Layout › Setup › Sheet options