Rabbi Leibtag shiurim: The Hebrew Calendar and its Missing Years- Parts 1 - 3
I already have the calculations done for you in my blog. Rabbi Liebtag gave shiurim based on the Seder Olam and Rabbi Breuer's discussion of the time between the destruction of the first temple and the building of the second temple. Note that this explains why we use 5777 for this year. Any time before Adam is considered not relevant. It does not matter whether is was six days or six "time periods". The count of time did not start until after the creation of Adam.
The geneologies used are based on the number of years given from the birth of each person until the birth of his son. Thus we have a table like this.
Name Father’s age at time of birth Year of birth
Adam N/A 0
Sheit 130 130
Enosh 105 235
Keinan 90 325
Mahalaleil 70 395
Yered 65 460
Chanoch 162 622
Metushelach 65 687
Lemech 187 874
Noach 182 1056
And Noach was 600 years in 1656 when the flood came.