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‪Basic numerical and arithmetic skills are impaired in individuals with intellectual developmental disabilities (IDD). Recent studies show that finger use is a procedure that can facilitate the construction of these skills in typically developing children. The purpose of this study is to characterize the use of fingers in students with IDD when solving small verbal and arithmetic problems. It also investigates the relationships between selected components of manual motor skills, finger use, and early numerical and arithmetical skills. Results indicate that students with IDD, on average 10 years and 4 months of age, frequently use fingers to solve arithmetic and verbal problems and that this procedure most often leads to success. As with typically developing children, visual-motor skills, also known as dexterity, appear to be the key to using this procedure. These results allow us to consider the potential benefit of an explicit teaching device for the use of fingers in mathematics for students with intellectual developmental disorders.‪