I want to create a spreadsheet that has a column with a date eg 04/02/2019 then another column that has a time period, eg 3 years & 10 months & 3 days. I want another column with the result of the date (04/02/2019) minus the total years, months & days = another date which is 3 years & 10 months & 3 days before 04/02/2019. The problems I foresee are knowing when there is a leap year and the number of days in the months prior to the original date. Is it possible to create something like this or is it too hard?