Definition
Dyscalculia is classified in DSM-5 as "specific learning disorder with impairment in mathematics" and in ICD-11 as "developmental learning disorder with impairment in mathematics". In Turkish practice it is used interchangeably with "mathematics learning difficulty".
Genetic, neurobiological and epidemiological evidence points to functional differences in brain regions associated with numerical cognition, notably the intraparietal sulcus (Mutlu & Akgün, 2017; von Aster & Shalev, 2007).
How common is it?
International studies report prevalence between 3% and 7% (Butterworth, 2005). Screening studies in Türkiye give similar figures: on average one or two children per classroom are at risk (Mutlu & Korkmaz, 2020).
Although as common as dyslexia, it is far less recognised, so most children move through school labelled as "not liking maths" without ever receiving support.
Signs by age
Preschool (4–6)
- Delay in learning to count; mixing up the number sequence
- Cannot see small quantities at a glance (subitising: three objects are not instantly "three")
- Cannot tell which of two groups has more
- No link between a numeral and the quantity it stands for
Primary school (6–10)
- Persistent finger counting for simple addition and subtraction; arithmetic facts never stick
- Place value not understood (35 and 53 confused)
- Marked difficulty reading a clock; hour and minute hands confused
- Large errors when estimating on a number line
- Not knowing which operation a word problem calls for
- Maths anxiety and homework avoidance
Secondary school
- Times tables never consolidate
- Lasting confusion with fractions, decimals and percentages
- Steps skipped in multi-step procedures
- Difficulty with time planning and handling money
Adulthood
- Avoiding change, budgets and bills
- Trouble with directions, left–right and map reading
- Poor time estimation; arriving late
- Avoiding jobs that involve numbers; low self-efficacy
Causes
The exact cause is still debated and two main accounts exist. The domain-specific deficit hypothesis points to impairment of innate core number knowledge (the approximate number system and the object-tracking system). The domain-general deficit hypothesis focuses on weaknesses in working memory, executive functions and attention control (Mutlu & Akgün, 2017).
In practice both mechanisms may be involved, which is why a good assessment measures numerical and cognitive skills together.
Dyscalculia vs dyslexia, and co-occurrence
Dyslexia is a specific difficulty with reading and writing; dyscalculia with number and mathematics. Both are neurological in origin and co-occur in 30–40% of cases. They involve different brain networks and call for different interventions. Co-occurrence with ADHD is also common.
How diagnosis works
A formal diagnosis is made by a child and adolescent psychiatrist or a clinical psychologist; in Türkiye, Guidance and Research Centres (RAM) handle educational evaluation and support plans. School counsellors and teachers play a critical role in screening and referral.
The Multiple Filter Model proposed by Mutlu and Akgün (2017) combines five filters to reduce reliance on any single test: teacher judgement, a pre-assessment test, a dyscalculia screening tool, a student information form and an intelligence assessment.
The screening tests on this site are the first link in that chain: they flag risk, they do not diagnose.
Principles of intervention
Effective intervention starts early, runs in short frequent sessions, moves from concrete to abstract (Concrete–Representational–Abstract, CRA) and uses the three representations of number together: digit, word and magnitude (Triple-Code Model, Dehaene 1992).
DokunSay materials cover the concrete stage, the Galaksay platform the adaptive practice stage, and our training programmes give teachers and parents the method.
Screening ≠ diagnosis. Results do not replace a professional assessment.
Key references
- Mutlu, Y., & Akgün, L. (2017). A new model proposal for diagnosing mathematics learning difficulty: the Multiple Filter Model. Elementary Education Online, 16(3), 1153–1173.
- Mutlu, Y., & Korkmaz, E. (2020). Investigating clock reading skills of third graders with and without dyscalculia risk. IOJPE, 9(1).
- Butterworth, B. (2005). The development of arithmetical abilities. Journal of Child Psychology and Psychiatry, 46(1), 3–18.
- von Aster, M. G., & Shalev, R. S. (2007). Number development and developmental dyscalculia. Developmental Medicine & Child Neurology, 49(11), 868–873.
- Dehaene, S. (1992). Varieties of numerical abilities. Cognition, 44(1–2), 1–42.