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== How to calculate by hand - Estimated date == | == How to calculate by hand - Estimated date == | ||
There is what is called a 30-day-month/or '''**8870''' method which assumes that all months have 30 days, many of the headstones and obituary ages at death appear to have been computed using this method. It's an approximation which agrees with the exact calendar month method about 2/3 of the time. | There is what is called a 30-day-month/or '''**8870''' method which assumes that all months have 30 days, many of the headstones and obituary ages at death appear to have been computed using this method. ''It's an approximation which agrees with the exact calendar month method about 2/3 of the time.''<br> | ||
When the online calculator is not available, use the '''**8870 formula''' or the 30 day month length <ref>[http://www.searchforancestors.com/utility/birthday.html Search for ancestors]</ref> | When the online calculator is not available, use the '''**8870 formula''' or the 30 day month length <ref>[http://www.searchforancestors.com/utility/birthday.html Search for ancestors]</ref> | ||
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