The article aims at drawing attention to the need of adequate IT preparation of to-be teacher, since in the constantly changing environment students use a computer, calculator or other multimedia more and more often. Therefore there is a need to show them the opportunities to use above mentioned devices to support teaching and learning process. We should remember, that a computer or calculator are modern appliances which support teacher's work, but to make them modern didactic measures a teacher should use them properly, as any tool itself is didactic in its nature . Regardless of which didactic tools are being used, we manage teaching process and a calculator or a computer should not do that instead of us.