100 years old now in 2023 - what year born?

Today, 26 March 2023 if a person is 100 years old now, what year was he born? See below:

If 100 years old, year of birth is:
1922 or 1923*

*It depends on whether he was born before or after 1 January 1923.

If now 100 years and his year of birth 1922 if he was born after 26 March 1922 until 31 december 1922 inclusively, and his year of birth is 1923 if he was born from 1 January 1923 to 26 March 1923.

Other examples:

If now 12 years, year of birth 2010 or 2011
If now 17 years, year of birth 2005 or 2006
If now 20 years, year of birth 2002 or 2003
If now 98 years, year of birth 1924 or 1925

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