1996 + 21 = 2017
People turning 21 in 2017 were born in 1996
21 decades after 2017 will be 2227.
If you were born in 1999 you would graduate from high school in the year of 2017.
You were born in 1947 if you have had your birthday in 2017, or else 1946.
Subtract 22-2017 and you get the year they were born. Easy peasy.
As of 2017, you were either born in 1986 or 1987
If you celebrated your 13th birthday this year (2017) - you were born in 2004 !
2017-73=
If you are 20 in 2017, then you were born in 1997.
2017 − 42 = 1975 was the year of birth.
February 21 over a year later so 21/11/2017 > 21/02/2019 for example
You would have been born in 1977.