Each finger has a definite numerical value when a whorl type pattern is present. The total of these values make up the Primary.
The numerator is made up of the total sum of the values present in the even numbered fingers (2, 4, 6, 8, 10) plus one.
The denominator is made up of the total sum of the values present in the odd numbered fingers (1, 3, 5, 7, 9) plus one.