It is the German numbering system for organizing genealogical information. The number of an individual's mother is twice the number of the individual plus one.
MALE ancestors have EVEN numbers.
The number of an individual's father is twice the number of the individual. Start by writing your name in the center circle. Continue to carefully fill out the remaining generations. Although I have taken every effort with the deciphering of the difficult handwriting, I may have interpreted some characters with minor incorrect spelling. Names are followed by birth dates, place of birth, occupation where given, date of death and place of death.