| It is obvious that for success in school mathematics | | | | from the first group had no problems, 87% of the |
| it is necessary to master elementary mental | | | | pupils from the second and third groups had big |
| computational skills at first - addition and subtraction | | | | problems, and the other pupils' results were, to put it |
| within the limits of 20, multiplication and division within | | | | mildly, very poor. Therefore it was confirmed that |
| the limits of 100. In spite of this there are kids in | | | | unsatisfactory development of the elementary |
| third, fourth, and fifth grade who cannot - without a | | | | mental computational skills in primary school was the |
| calculator - add 8 to 5, subtract 7 from 12, multiply 7 | | | | first cause of difficulties in math's learning. It means |
| by 8, divide 54 by 9 and so on. Just those very pupils | | | | that results of testing of the skills may be used for |
| have considerable difficulties while learning the other | | | | prognosis of failure in school mathematics. |
| basic topics of arithmetic and algebra. They cannot | | | | It is evident that the population of pupils with |
| master well operations with two and three digit | | | | satisfactory skills may be represented only by the |
| numbers, common fractions, negative numbers, like | | | | pupils from the first group. That's why the |
| terms, brackets, simple equations etc. Even | | | | parameters of the first group were used as the basis |
| calculators cannot help them. | | | | for computing limits of values of the considered |
| For confirming the influence of quality of elementary | | | | parameters. In view of the fact that sample statistics |
| mental computational skills over success in school | | | | only approximately estimate parameters of |
| mathematics I had decided to investigate a level of | | | | population, the top border under which 90% of |
| the skills of pupils in graduation-classes of primary | | | | samples means lie was considered as the |
| school (the multiplication table had been completely | | | | starting-point (the sample mean of satisfactory |
| learnt a year and a half ago) and their achievements | | | | achieving pupils), and only the 99th percentile of thus |
| in algebra three years later. The study was carried | | | | achieved normal distribution was taken as the limit for |
| out in period from 1994 to 2004 years. The sample | | | | time and the last value of thus achieved Poisson's |
| includes 403 pupils. Standard tables including 64 | | | | distribution which probability is not less than 0.01 was |
| elementary operations in addition, subtraction, | | | | taken as the limit for number of errors. This method |
| multiplication and division were used for determination | | | | of determination of limit values gives approximation |
| of the level of the skills. You can see specimens of | | | | with surplus only. Therefore the permissible limits of |
| the tables at my site Prevention of Failure in School | | | | time and errors may be considered as sufficiently mild |
| Mathematics (Improvement of Elementary | | | | demands. |
| Computational Skills, Tables). | | | | The limit values were calculated for the standard |
| The pupils completed the tables in written form. The | | | | tables including 64 similar elementary operations. For |
| time from the starting point to the finishing point was | | | | final-year pupils of primary school (the multiplication |
| measured. For estimation of the level two criteria | | | | table had been completely learnt a year and a half |
| were used - a total time of completion of a table and | | | | ago) the next limit values had been obtained: |
| a number of occurred errors. Statistical analysis of | | | | Addition - 11 minutes 02 seconds and not more than |
| the results had shown that there is possible to single | | | | 4 errors. |
| out four uniform groups in the sample: | | | | Subtraction - 11 minutes 35 seconds and not more |
| 1) Pupils completed the tables quickly and made not | | | | than 4 errors. |
| more than 3 mistakes. | | | | Multiplication - 9 minutes 46 seconds and not more |
| 2) Pupils completed the tables significantly slower | | | | than 3 errors. |
| than the pupils from the first group but made not | | | | Division - 9 minutes 06 seconds and not more than 3 |
| more than 1 mistake. | | | | errors. |
| 3) Pupils completed the tables at middle pace and | | | | This level of elementary mental computational skills is |
| made 3-6 mistakes. | | | | a good means for determination of pupil's |
| 4) Either a time or a number of errors, or both | | | | preparedness for successful studies. The limit values |
| together were evidently "good-for-nothing". | | | | of the considered parameters define the first |
| Statistical analysis of the parameters of the first | | | | threshold of school math's learning ability. The pupils |
| groups (separately for addition, subtraction, | | | | who have not crossed this threshold are doomed to |
| multiplication and division) confirmed (significance at | | | | poor progress. The prediction of their failure in math |
| 5% level) their internal uniformity: distribution in time is | | | | will be right in about 95 cases of 100. |
| normal, and distribution in errors submits to Poisson's | | | | It must be noted in conclusion that the level of |
| law. In different cases these groups included from | | | | elementary mental computational skills of actively |
| 50% to 70% of corresponding samples. According to | | | | working pupils only do not decreases in due course. If |
| the criteria of rejecting extreme values they were | | | | a pupil uses a calculator instead of mental |
| sufficiently good isolated (significance at 5% level) | | | | computations, works passively at lessons and does |
| from the other parts of the samples. | | | | not carry out home works himself/herself, then the |
| In three years after the testing the current results in | | | | level decreases gradually. In certain cases it leads to |
| algebra (of the pupils which had been tested) during | | | | difficulties in math's learning. |
| five months was studied. It turned out that all pupils | | | | |