1. It's easy to count up the years between Adam and the flood (about 1500 years).
2. From the flood to Abraham is about 300 years and from Abraham to Israel leaving Egypt, about 400 years = about 700 years.
So far, that's about 2200 years.
3. Israel's independence as a nation: about 1300 years from their exodus out of Egypt to the Babylonian captivity. (Side note: remarkable that Israel was an independent and free nation for so long.)
So far, that's about 3500 years.
4. The book of Daniel tells us it's about 500 years from the Babylonian captivity to Christ.
5. It's been about 2000 years since Christ.
There you have it.
That creates a chronology problem for creationists. Creation was around 4000BC, but the Flood was around 2500BC. In the Flood, the human race supposedly perished except for Noah's extended family.
The chronology problem is that there are civilizations whose records extend past 2500BC, like Sumeria, Egypt, Indian, etc. Written records spanning the time line, of large and vigorous civilizations.