Low numbers — or low series — refer to cards from the first series produced in a given set for that year. These are the cards that hit the market first, with the broadest production and distribution.
Low series cards often feature some of the most valuable and sought-after players in the set. Because they're the first cards available each season, they get the most attention from collectors and tend to generate the most excitement.
The distinction between low and high numbers matters most in vintage collecting, where production differences between series were significant. Knowing whether a card is from the low or high series can directly impact its scarcity and value.