How many years from AD79 to 2010?

Answer 1

From the beginning of year AD 79 through the end of AD 2010, you have a length of 1,932 years. Clearly the length of time can vary, depending on what points of the years you refer to. From the very end of AD 79 to the very beginning of AD 2010, you would have 1,930 years.

For 'discrete' variables, or 'whole' units, like numbered tickets, or 'whole' years, generally you subtract the smaller from the larger and add one. Don't believe me? Take numbered tickets as an example. Say that you buy tickets numbered 4 through 19, including tickets 4 and 19. If you just subtract you get 15. But count the tickets in your head. There are 16!

If you find 4 on the number line, and then find 19 on the number line, and count the 'whole' spans between them, you will count 15, because you are counting all of the 4 span, but none of the 19 span except one single dimensionless point. But above, 19 is the number of a whole ticket.

In this case, years are interesting. You can think of them as 'discrete', if every year in the time span is complete, like a concert ticket. You can also think of them as 'continuous', since you can start reckoning from any moment of the start year, through any moment of the ending year.