The serial number isn't really useful in giving a value. Post a new question and include information like the series (date) and condition.
Depends on year and how low the serial number is.
The percentage of a partial bill really has little to do with its value. Any bill is worth its face value if it contains a complete serial number and any part of the other serial number.
$20
$10
The serial number alone isn't enough to assign value, but rather the series year and the condition. Without more information, it's assumed to be worth one dollar.
The value is more dependent on the year (series) of the bill. The serial number by itself isn't enough information.
Face value.
As you have seen in many other postings, a bill's serial number almost never has anything to do with its value.
A 20-dollar bill with one serial number is still worth 20 dollars, as the value of the bill is determined by its denomination rather than the number of serial numbers it has. Each U.S. currency note has a unique serial number, but this does not affect its face value. Therefore, regardless of the serial number, the bill retains its worth of 20 dollars.
$20
$5
The value is determined by the series (date) and condition.