“Cite the false premises, please”
The first would be thinking that there is information in the Bible that would allow one to calculate years elapsed since the big bang (or whatever event heralded the beginning of the universe).
And that’s really enough. If you don’t have the data required, you can’t perform the calculation.
The ages of the people (Adam ff) and the reigns of the kings bring us back to the Biblical creation of man.
“years elapsed since the big bang”
Do you mind specifying location?
That is, are you referring to years elapsed in your current location, or to years elapsed in the precise location of the “big bang?”
Remember, time is relative to space—not only to itself.