James Ussher (1581 - 1656 AD) Bishop of Armagh, Ireland, in his own time was thought to be a scholar. He knew the dates for the reign of Nebuchadnezzar, second ruler of the Neo-Babylonian Empire. This king sacked Jerusalem twice, first in 597 BC, the second time he destroyed it, in 588 BC. These events and some of the Hebrew leaders involved, such as Daniel, are mentioned in the Old Testament of the Bible. Bishop Ussher then used the dating of the Bible to fix the Creation in Genesis as in 4004 BC.

The Jehovah's Witnesses may be ridiculed by some for their persistence in proselytizing, but they are indefatigable students of the Bible. Their Aids to Bible Understanding has 1696 pages packed with mostly useful information. On page 333 under Chronology, it says

From the creation of Adam, 4026 BCE

That's 'Before Christian Era,' or 'Before Common Era' or BC. They have the reign of Nebuchadnezzar dated 624 BCE to 581 BCE, whereas my Encycopaedic Dictionary dates it as 605 BC - 562 BC. I suspect this difference is mainly responsible for the 22 year difference between the two dates we have for the Creation. But here we're not concerned with such small differences, so let's say that Genesis gives us a Creation date of about 4000 BC. Here's how this becomes possible, Genesis chapter 5:

3. And Adam lived an hundred and thirty years, and begat (a son) in his own likeness, after his image, and called his name Seth.

4. And the days of Adam after he had begotten Seth were eight hundred years: and he begat sons and daughters:

5. And all the days that Adam lived were nine hundred and thirty years: and he died.

6. And Seth lived an hundred and five years, and begat Enos:

7. And Seth lived after he begat Enos eight hundred and seven years, and begat sons and daughters:

8. And all the days of Seth were nine hundred and twelve years: and he died.

9. And Enos lived ninety years, and begat Cainan:

and so on. Genesis chapter 4 had a genealogy for Cain described in the same way. I'd like us to compare some of the entries in these two lines of descent given in Genesis:

Enoch Enos
Irad Jared
Mehujael Mahalaleel
Methusael Methusaleh
Lamech Lamech
Naameh (female) Noah

My suggestion is that here we have only one line of descent. The variations show how the different strands, or traditions, or versions or texts, from different areas gradually drifted apart, but came from one source originally. In this case it may be because religious scribes did not want mankind to have been descended from a murderer (Cain). Knowing how corrupt some of the text is which we have to work with, plus translation difficulties and biases, it is hazardous to date the Creation date in the Bible from the information in the Bible. There may well be omissions along the way, even if the actual ages given are accepted. But we cannot do more than use what we have, so let's say the Creation according to the Bible was about 4000 BC. Next we need to see what archaeologists, pre-historians and historians tell us was going on in the area the Bible is involved with, the Middle East, at the time the Bible indicates the Creation took place.