"8870"
Gravestones often supply only the Date of Death and Age.
A swift way to calculate the date of birth is as follows:
Suppose a person died May 6, 1889 at the age of 71 years, 7 months and 9 days:
1. Write the Death date year, month, day as............. 18890506
2. Subtract the age at death.......................................... 710709
3. This gives the figure ............................................ 18179797
4. Now subtract 8870 ....................................................8870
5. The result is .......................................................18170927
Which reads as year 1817, 9th month (September), 27th day
http://www.onhgs.org/bdatecalc.htm
