ad-di-tive in num-bers
/ˈæd.ə.tɪv ɪn ˈnʌm.bərz/
In Hellenistic astrology, additive in numbers is a phrase used in discussions of planetary motion, generally referring to a planet in direct motion.
Hellenistic authors used this expression together with subtractive in numbers, which generally referred to retrograde motion. The phrase describes a planet's manner of motion in numerical terms, reflecting whether its position increases through the zodiac. Some discussion has extended the term to questions of increasing or decreasing speed, but that distinction is more accurately described through language about moving toward the greater or lesser extent of a planet's course. In this context, additive in numbers belongs to the technical vocabulary of planetary motion rather than to a separate interpretive doctrine.