The Numberjacks are animated characters (the numbers 0 to 9) who live in an ordinary sofa and solve problems outside; each episode has the same structure. At the beginning of the episode, some of the Numberjacks are engaged in an activity, that would have relevance to the problem that is later discovered - then, an "agent" (who was a live-action child) calls in and describes the problem that is occurring. One (or two) of the Numberjacks go out into the real world to solve the problem while the remaining Numberjacks stay in the sofa and watch their progress on a screen. As soon as the problem is understood, 5 imagines what else could go wrong if the problem wasn't solved (often wondering what would happen to the Dancing Cow, who never actually made any physical appearance in the real world). Once outside, the Numberjacks are shown in a live-action setting (although themselves still animated); they diagnose their problems by examination, and with help from additional ideas from the agents, who call into the base. The problem can either be caused by one of the antagonists, or one of the younger Numberjacks (0, 1 or 2) escaping from the sofa and inadvertently making things go wrong. Problems are solved by using "Brain Gain," a magical force of power activated by use of a machine in the sofa and transferred to the Numberjack. Once the problem is solved, the Numberjacks return to their base, replay what happened on a screen and then challenge the viewer to think about a related problem and "call the Numberjacks"; the problems encountered are all based upon simple mathematical concepts, and the programme is intended to stimulate young children's interest in mathematics. On satellite, digital, and cable TV, a link to Numberjacks often appeared in the corner of the screen and sometimes on (for example) gardening programmes as a way of helping people with basic numeracy.