The results of the pedagogical experiment to clarify the number of dynamic mathematics software, which modern math teacher should know, are described.Quantitative results of the questionnaire survey of math teachers concerning the use of DMS in the learning process are given. Thus, the preferences of the teachers are software Gran and GeoGebra, the preferences of the students are software GeoGebra and MathKit. It is noted that math teachers in determining the number of DMS, which they should know and be able to use in the future, notice 3-5 DMS and students, future math teachers, notice 5-7 DMS. Statistical processing of the results was made based on the sign test. It allowed to justify the conclusion, that the study of 5 DMS is needed, at the significance level of 0.05.