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Neurodiversity and Co-occurring differences

Dyscalculia and maths difficulties

Dyslexia can occur in association with dyscalculia. Co-occurrence of learning disorders appears to be the rule rather than the exception and is believed to be a consequence of risk factors that are shared between disorders, for example, working memory. However, it should not be assumed that all dyslexics have problems with mathematics, although the percentage may be very high, or that all dyscalculics have problems with reading and writing.

Dyscalculia definition

Dyscalculia is a specific and persistent difficulty in understanding numbers which can lead to a diverse range of difficulties with mathematics. It will be unexpected in relation to age, level of education and experience and occurs across all ages and abilities.

Mathematics difficulties are best thought of as a continuum, not a distinct category, and they have many causal factors. Dyscalculia falls at one end of the spectrum and will be distinguishable from other maths issues due to the severity of difficulties with number sense, including subitising, symbolic and non-symbolic magnitude comparison, and ordering. It can occur singly but often co-occurs with other specific learning difficulties, mathematics anxiety and medical conditions.

BDA/SASC (2019)

Because definitions and diagnoses of dyscalculia are in their infancy and sometimes contradictory, it is difficult to suggest a prevalence, but research suggests it is around 5%. However, ‘mathematical learning difficulties’ are certainly not in their infancy and are very prevalent and often devastating in their impact on schooling, further and higher education and jobs. Prevalence in the UK is at least 25%.

Signs of dyscalculia

A person with dyscalculia/mathematical learning difficulties may:

  • Have difficulty when counting backwards.
  • Have a poor sense of number and estimation.
  • Have difficulty in remembering ‘basic’ facts, despite many hours of practice/rote learning.
  • Have no strategies to compensate for lack of recall, other than to use counting.
  • Have difficulty in understanding place value and the role of zero in the Arabic/Hindu number system.
  • Have no sense of whether any answers that are obtained are right or nearly right.
  • Be slower to perform calculations. (Therefore give fewer examples, rather than more time).
  • Forget mathematical procedures, especially as they become more complex, for example ‘long’ division. Addition is often the default operation. The other operations are usually very poorly executed (or avoided altogether).
  • Avoid tasks that are perceived as difficult and likely to result in a wrong answer.
  • Have weak mental arithmetic skills.
  • Have high levels of mathematics anxiety.


Dyscalculia is difficult to identify via a single diagnostic test. Diagnosis and assessment should use a range of measures, a test protocol, to identify which factors are creating problems for the learner. Although online tests can be of help, understanding the difficulties will be better achieved by an individual person-to-person diagnostic, clinical interview.

More information

Maths Learning Difficulties, Dyslexia and Dyscalculia (Oct 2018)
This BDA publication is available to purchase from our shop.

Policy, Research, Identification and Intervention for Maths Learning Difficulties and Dyscalculia (2015): BDA Dyscalculia Committee.

Maths Explained video tutorials created by Dr. Steve Chinn, a leading authority in the field of dyscalculia.