Dyscalculia is defined as an impairment of basic arithmetic skills (addition, subtraction, multiplication, division), which cannot solely be explained by a general intelligence deficit nor by inadequate learning environment (ICD-10: Dilling et al., 1993).
In the ICD-11, (developmental) dyscalculia is described as a developmental learning disorder that is characterized by a lack of “skills related to mathematics or arithmetic, such as number sense, memorization of number facts, accurate calculation, fluent calculation, and accurate mathematic reasoning” (World Health Organization, 2020).

Dyscalculia is a Specific Learning Disability now known to affect around 6% of the population. Dyscalculia is highly comorbid with both Dyslexia and ADHD but Dyscalculia is a separate disorder that should be treated accordingly.

Research shows that indicators for developing Dyscalculia can already be detected in 5-6-month-old babies. The researchers discovered that they are attentive towards “numerosities” – in other words, core systems. This is an important discovery not least because these inborn core mechanisms enable fast-track learning. If this core system is not functioning properly, it can be seen long before children enter school.

Doing arithmetic requires a highly specified neuro-cognitive network. The starting point for the development of this network is an early core mechanism. Dyscalculia results when this core mechanism is deficient. Karin Landerl, 2010: Dyscalculia – the Neglected Learning Disability. University of Tuebingen, Germany.

Different people have a range of mathematical abilities – some people have minor problems and react well to being taught in a different way, while other children and adults have more serious problems. Partly these differences seem to stem from the ability to concentrate, so they may be influenced by coexisting conditions – Two Dyscalculia Subtypes With Similar, Low Comorbidity Profiles: A Mixture Model Analysis (2021).

Dyscalculia can include

  • Math concepts, numbers, and reasoning.
  • Remembering math facts.
  • Executing maths procedures.
  • Solving mental math.
  • Reading clocks to tell time, and time awareness.
  • Calendars, schedules and dates, planning and organisation.
  • Counting money.
  • Identifying patterns.
  • Sequences – like phone numbers, addresses, passwords, codes, directions and maps (left and right, up and down, navigating).
  • Visual-spatial memory.

For example, mental number line tasks, which require participants to locate a given number on a number line, or the ability to convert auditorily presented numbers into written Arabic symbols (transcoding; Nuerk et al., 2006; Kuhn et al., 2013, 2017).

Frequently Asked Questions

Is Dyscalculia the same as “Dyslexia with numbers” or “math Dyslexia”?

  • The difference between dyslexia and dyscalculia – read more here.
  • Dyscalculia By Any Other Name… – read more here.

Does dyscalculia affect all types of maths?

Some adults with severe dyscalculia can even be very good at geometry and using statistical packages, and capable of doing college-level computer programming. So it doesn’t affect all mathematical abilities or skills.
Read more here.


Panayiotis Constantinides
Panayiotis Constantinides is an English teacher, certified oral examiner and licensed Dyslexia evaluator. He lives in Greece. Speaker about Dyslexia, Dysanagnosia, Dysgraphia, Dysorthography, Dyscalculia, Dyspraxia.

Prof. Dr Annemie Desoete
Dyscalculia & Dyslexia, ADHD and DCD (also called Dyspraxia).
Prof. Dr. Desoete, is a Full Professor at Ghent University and Artevelde University College (Ghent).
Prof. Dr. Desoete has extensive experience in research in early characteristics of learning disabilities (dyscalculia, dyslexia).

Bhu Venkatesan (OT)
(OT – Paediatric Occupational Therapist) Dysgraphia, Dyslexia, Dyscalculia.
Useful resource

Helmy Faber
Author of ‘The Math Handbook for students who have math difficulties/anxiety, Dyscalculia, Dyslexia, ADHD’.


Dyslexia can be best described as a range of difficulties that make the acquisition of reading, spelling, writing and sometimes mathematics difficult for those afflicted.

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Attention Deficit Hyperactivity Disorder (ADHD) is characterised by differences in attention, hyperactivity, and impulsivity.

Read more

Dysgraphia affects writing, especially handwriting, and also how the letters formed. The word comes from Greek – dys meaning ‘impaired’ and graphia meaning ‘writing by hand’.

Read more