Final answer:
The most appropriate date format for a nurse to use for spreadsheet calculations would typically be a numerical format like 'YYYY-MM-DD' or 'MM/DD/YYYY' to allow the spreadsheet software to recognize it as a date.
Step-by-step explanation:
When a nurse is preparing to insert a date into a spreadsheet for use in calculations, the most appropriate format would depend on how the spreadsheet is intended to be used. However, in general, for calculations involving dates, a numerical format such as 'YYYY-MM-DD' or 'MM/DD/YYYY' would be most suitable. This allows the spreadsheet software to recognize the input as a date value, facilitating various date calculations and sorting tasks that might be needed in data analysis.