Is it possible to use calculators on lessons of Mathematics? This question is asked by every teacher of Mathematics. Among teachers we can distinguish real opponents as well as enthusiasts. Researchers are also trying to seek for the answer, they carry out experiments and observe activities of the examined. Those ones, who consequently reject applying even the simplest calculators on lessons of Mathematics, claim that every pupil at school should “make calculations in mind well”. Simultaneously they state, that the tasks ought to be adjusted to intellectual possibilities of a child. What attitude to apply if there is a pupil able to solve even complicated tasks, but he or she makes mistakes in calculations? Which engineer will we go to, this one, who uses a calculator to eliminate accidental mistakes made unintentionally while concentrating on more essential issues, or to such an engineer, who “makes calculations in his mind” but his bridges break up? Mathematics is a difficult subject in a school repertoire, we are searching for new syllabi, and together with them, suitable books to make our and our pupils’ work easier. Maybe it is enough to change the conception of our work and start visualization of Mathematics. A calculator can become a cheep tool enabling to overcome difficulties and emotional barriers. Work with a calculator is mobilizing for pupils. Contact with this tool influences on creating additional, positive emotions.