F81.2
Specific disorder of arithmetical skills
Coding guidance (WHO 2019)
Involves a specific impairment in arithmetical skills that is not solely explicable on the basis of general mental retardation or of inadequate schooling. The deficit concerns mastery of basic computational skills of addition, subtraction, multiplication, and division rather than of the more abstract mathematical skills involved in algebra, trigonometry, geometry, or calculus. Developmental: acalculia arithmetical disorder Gerstmann syndrome Excl.: acalculia NOS (R48.8) arithmetical difficulties: associated with a reading or spelling disorder (F81.3) due to inadequate teaching (Z55.8)