Emperor Octavian died 120 years later after Emperor Augustus was born. The sum of the ages of both at death was 100 years.
if we know that Emperor Augustus died in 10 d. C.,
In what year was Emperor Octavio born?
If between the two they lived 100 years and Octavio died 120 years after Augustus was born, then Octavio was born 20 years after Augustus died, therefore He was born in 11 BC since there was no year 0.