Thank you, John, Rick, and Lee for explaining the proper way of calculating the putative date of birth. On stones I've seen with birth and death dates plus years-months-days, it worked correctly whether working forward (from the date of birth) or backward (from the date of death). Lee, you solved the puzzle for me--every month is 30 days--so that, ok, 22 Feb to 22 Mar is one month; then 9 days left in March to day of death, 15 Apr, boom, that's 24. So, it works correctly working forward as well as backward. That's what puzzled me when I wondered about Feb. plus a leap year because when someone dies, one starts with the deceased's age at the last birthday and works forward to the day of death and it makes sense to ignore the actual number of days in each month. I was overthinking it after all. Thanks again to each of you. Sam On Tue, Sep 22, 2015 at 12:13 PM, John Cardinal via <tmg@rootsweb.com> wrote: > Sam, > > I think it works from smallest (days) to largest (years) when subtracting > dates. > > First, subtract the days from the given date. You started with 15 April > 1864, so subtract 24 days and you get 22 March 1864. > > Next, subtract a month, that yields 22 February 1864. > > Last, subtract 50 years, that yields 22 February 1814. > > John >