1. Learning Skill Disorders
DYSLEXIAS
DYSGRAPHIAS
DYSORTHOGRAPHIAS
DISORDERS IN THE ARITHMETICAL AND NUMERICAL SKILLS
DYSCALCULIAS

2. Calculation disturbances
Among the Learning Skill Disturbances, calculation disturbances, even if extremely important and widespread, are less studied and known than other disorders.
That is why rehabilitation plans are scarce and not so valid.

3. Cut-off
In the continuum going from exceptional to scarce performances, the cut-off between “normality” and“pathology” is represented by a score to a specific standard test which is at least two standard deviations (- 2 SD) below the expected level, based on the age and general intelligence of the child.

4. Exclusion Criterion
Even for Dyscalculia, the exclusion criterion is the presence of a mental retard (IQ less than 70).
For diagnostic purposes, the following assessments must be carried out:
Neurological
Neuropsychological ( general cognitive, linguistic and video-spacial skills )
Attention and memory
Psychological (self-evaluation, motivation, personality).

5. Statistical distribution and cut-off

6. Prevalence (= essential knowledge)
As for the datum of prevalence, the calculation disorder affects in an isolated way 3% of the school population
It is associated to reading and writing disorders in 2,5 to 3% of cases

7. Dyscalculias Classification
Inability in number reading and writing if lexical mistakes are present
DYSLEXIA FOR DIGITS
Difficulties in acquiring procedures and calculation algorythms with mistakes in putting in columns, amounts carried over and borrows …
PROCEDURAL DYSLEXIA
Difficulties in memorizing multiplication tables, numeric sequences, mental calculation, etc.
DYSCALCULIA FOR
ARITHMETIC FACTS

8. Incidence of the dyscalculic disorder
From a research dating back to 1996 carried out on people aged between 10 and 11, the incidence was:
Dyscalculic people : 6,1%
Dyslexic people: 6,5%
Only Dyscalculic people : 5,4%
R. Shalev et al. (1996)

9. Evolution between the age of 8 and 11
According to data emerged in a recent research carried out on Italian children, with the passing age and the development of the required performance, one can observe an increase in the percentage:
NUMERICAL SKILLS
From 1% to about 6%
UNDERSTANDING AND THINKING SKILLS
From 8 to 14%

10. Skills deficit
 Understanding specific words, operations and mathematical concepts
Applying the symbolic reasoning to problems
Organizing objects according to common characteristics

11. Skills Deficit Recognizing mathematical symbols
 Copying numbers correctly
 Respecting the operations
 Counting objects carefully
 Learning the multiplication tables by heart
 Following a sequence of mathematical steps

12. PROCESSING SUBSYSTEMS
Understanding the number system
Understanding the calculation system
Understanding the production of numbers system

13. 1. Understanding the number system - Semantics
It regulates the understanding of quantity
Verbal code
/wʌn/
Arabic code 1

14. 1. Understanding the number system - Semantics
Verbal code
/θriː/
Arabic code 3

15. 1. Understanding the number system - Lexicon
It regulates the name of the number
Arabic code 1
/wʌn/

16. 1. Understanding the number system - Lexicon
Arabic code 11
/ɪˈlevn/

17. 1. Understanding of the number system - Syntax
It regulates the inner number grammar, that is place value of digits. The position occupied in space modifies the name e the value.
/tuː/ 2

18. 1. Understanding the number system - Syntax
/ˈtwentɪ/ 20

19. 2. Understanding the calculation system
It includes:
processing operation signs
(+ = sum; - = difference; x = product; / = division; ecc.)
Activation of number facts
(mnemonic calculation procedure (multiplication tables) mental calculation skills)
Calculation procedure
(algorythms, amounts carried over, ecc.)

20. 3. Understanding the production of numbers system
It represents the output of the system of calculation, and, this way, it gives the numerical answers thanks to an elaboration skill