Short Answer 
To determine someone’s age from their birth date, subtract the number of years since birth from the current year, leading to the birth year. For example, if someone was born 10 years ago in 2013 and it is now 2023, they would be 10 years old, noting that the calculation must be updated if the year changes.
Step 1: Understand Birth Year Calculation
To find out how old someone is based on their birth date, we first need to determine their birth year. If a person was born 10 years ago and we are currently in the year 2023, we can calculate the birth year by subtracting 10 from the current year.
- Current Year: 2023
- Calculation: 2023 – 10 = 2013
- Birth Year: 2013
Step 2: Calculate Current Age
Once we have established the birth year, the next step is to find out the person’s current age. The current age is simply the difference between the current year and the birth year we calculated. This helps us understand how many full years the person has lived.
- Current Year: 2023
- Birth Year: 2013
- Calculation: 2023 – 2013 = 10
Step 3: Acknowledge Variable Years
While we’ve determined that someone born 10 years ago is 10 years old in 2023, it is essential to recognize that this calculation is time-sensitive. If the current year changes, the age will also change correspondingly and needs to be recalculated.
- Current Year Changes: Update calculations accordingly.
- Example: If the current year is 2024, then 2024 – 2013 = 11 years old.
- Importance: Accurate age calculation relies on knowing the current year.