Does "It just doesn't add up" mean "it is not consistent"?

more like " there is a huge piece of information missing here or else someone is lying". it is mostly a call for more information so that the author can decide which is the problem here.

think of it as "the claimed result does not follow the equation as given, so either the result is wrong or the equation is wrong".

Would take this expression to mean: The facts don't lead to that conclusion, don't justify the conclusion. "Something's rotten in Denmark." Something is not kosher.

Both replies are equally useful and worthy to be chosen as Select Answer.
Thank you.

It means "it doesn't add up."