Can someone help me understand this ..?

Question

Examine years ago since the present time back round off present year to 2000

10,000 yrs ago = 8000 B.C.
1,000 yrs ago =1000 AD
3,000 yrs ago = 1000 BC
1500 AD = 500 yrs ago
2000 BC = 4000 yrs ago
3000 BC = 5000 yrs ago

can someone explain how to get the dates back to the years ago cause im not getting it

Answer 1

Assume the current year is 2000.

Count backward (subtract) the "years ago" amount from 2000 to get the year in question.

Thus, 1,000years ago = 2000 - 1000 = 1,000 AD
but 3,000 years ago = 2000 - 3000 = -1,000 which is 1,000BC since year 0 is the distinguishing year between AD and BC. Think in terms of a number line. Start on the positive side at 2,000 and count left to zero and then start again in the negative. If the result is negative, then the number is BC. If positive, it is AD.