How to determine the readability of a physics text

The educational text of textbooks of physics has many defects. It is necessary to underline its overcrowding with inaccessible materials for a pupil. The establishment of parameters the text difficult and set of aspects still needs to be distinguished. Under the term, «readership» the sum of those factors which promote successful reading, with the account as to complexity of the text, and preparation of level of the reader (age, formation) is meant. Complexity of the text consists in particular its maintenances, in logic construction, in it informed. The formula of complexity of the text should be simple. It is necessary to use numerical (empirical) coefficients into formulas. Purpose of these coefficients is clear mathematically: to counterbalance an order of members and to "open" an interval of a scale of difficulty. Factors are needed to be rounding. Usage of formulas doesn't exclude acknowledged and inculcation methods of checking the quality of textbooks. These methods keep their value. Formulas allow to improve methods of estimation of the quality of textbooks and to receive the united indexes of difficulty of material`s transferring on which basis it is possible to develop an objective criteria of optimum difficulty of the educational text.