Dyscalculia is difficulty in learning or comprehending arithmetic, such as difficulty in understanding numbers, learning how to manipulate numbers, and learning facts in mathematics. It is generally seen as a specific developmental disorder.
Dyscalculia can occur in people from across the whole IQ range, often, but not always, involving difficulties with time, measurement, and spatial reasoning. Estimates of the prevalence of dyscalculia range between 3 and 6% of the population. A quarter of children with dyscalculia have ADHD.
Dyscalculia involves frequent difficulties with everyday arithmetic tasks like the following:
Difficulty reading analog clocks[8]
Difficulty stating which of two numbers is larger
Inability to comprehend financial planning or budgeting, sometimes even at a basic level; for example, estimating the cost of the items in a shopping basket or balancing a checkbook
Difficulty with multiplication-tables, and subtraction-tables, addition tables, division tables, mental arithmetic, etc.
Difficulty with conceptualizing time and judging the passing of time. May be chronically late or early
Problems with differentiating between left and right
Inability to visualize mentally
Difficulty reading musical notation
Difficulty with choreographed dance steps
Difficulty working backwards in time, (e.g. What time to leave if needing to be somewhere at 'X' time)
Difficulty comprehending things relating to occurrences in different time zones
Difficulty navigating or mentally "turning" the map to face the current direction rather than the common North=Top usage
Having particular difficulty mentally estimating the measurement of an object or distance (e.g., whether something is 10 or 20 feet (3 or 6 meters) away).
Inability to grasp and remember mathematical concepts, rules, formulae, and sequences
Inability to concentrate on mentally intensive tasks
Mistaken recollection of names. Poor name/face retrieval. May substitute names beginning with same letter.
https://en.wikipedia.org/wiki/Dyscalculia