To calculate the date of birth, subtract the age (12 years, 5 months, and 18 days) from the given date (28-02-1978).

Step 1: Subtract the days

• Starting date: 28 February 1978
• Subtract 18 days: $28 - 18 = 10$
• Resulting date: 10 February 1978

Step 2: Subtract the months

• Starting month: February 1978
• Subtract 5 months: From February, count backward 5 months (February → January → December → November → October → September)
• Resulting month: September 1977

Step 3: Subtract the years

• Starting year: 1977
• Subtract 12 years: $1977 - 12 = 1965$

Final Result:

The person’s date of birth is 10 September 1965.

Would you like a detailed explanation or have further questions?

---

Here are 5 related questions for better understanding:

1. How do leap years affect such calculations?
2. What if the calculation spans across centuries?
3. How can such a calculation be automated using a formula?
4. How is age typically calculated in different calendars (e.g., Gregorian vs. Lunar)?
5. How to account for varying days in months for manual calculations?

Tip: Always verify results by adding the calculated age to the date of birth to ensure the end date matches.