For confirming the influence of quality of elementary mental computational skills over success in school mathematics bad achieving pupils (from one to three years after the multiplication table was completely studied) were chosen. The work upon development of the skills, which level had been very bad, was carried out with each of them individually. In 85% of cases the level was brought to stable correspondence to the calculated values of parameters. The results exceed the limit values of the parameters significantly. After that a work upon main basic topics of school math (common fractions, algebraic equations and so on) was carried out with the pupils. The work was successful, and all of them had not big problems in their subsequent math’s learning.

It must be noted that the level of elementary mental computational skills of actively working pupils only do not decreases in due course. If a pupil works passively at lessons and does not carry out home works himself/herself, the level decreases gradually. In some time it leads to difficulties in math’s learning.

Thus a level of elementary mental computational skills is a good means of determination of pupil’s preparedness for successful studies. The limit values of the considered parameters define the first threshold of school math’s learning ability. The pupils who have not crossed this threshold are doomed to poor progress. It means that results of testing of the skills may be used for prediction of failure in school mathematics.

MAIN INFERENCES

1) Unsatisfactory development of the elementary mental computational skills adverse affects progress in school mathematics. The skills must be driven to automatism. That is the obligatory condition for success in school mathematics.

2) A level of the skills may be determined by two parameters: average time of implementation of one operation and relative frequency of occurrence of errors.

3) For testing it is handy to use the standard tables, for which the permissible limits of time and errors were calculated.