Five investors sat on the original Dragon's Den panel when the BBC show launched.
The first panel consisted of Peter Jones, Duncan Bannatyne, Rachel Elnaugh, Doug Richard and Simon Woodroffe. This five-Dragon arrangement established the central visual and dramatic structure of the programme: entrepreneurs face a group of experienced investors and must try to secure money in exchange for a share of their company.
The panel changed over time as Dragons departed and new investors joined. That turnover is why different viewers may remember different line-ups as the show's original group. In particular, Deborah Meaden became one of the programme's most recognisable investors after joining in the second series, but she was not part of the launch panel.
The five-investor format also means that a pitch can receive several competing offers, a single offer or no offer at all. The number refers to the regular panel at launch, not to every guest investor or occasional substitute who has appeared in later series.