In this study, lessons on coordinate, percentage, and factorization in prime factors were taken with TI-73 calculator for 20 elementary school students in the 5th grade math gifted class in Pohang city. Through these lessons, the researcher examined with cases how using the calculator would influenced the lessons for the gifted students, and attempted to obtain implications on using calculators as learning tools in class. Activity sheets were made for this study and a 80-minute lesson was held three times for three weeks. In order to collect data, the class was recorded on videotape, the students were interviewed, and documents used in the class were collected. Then all the data were transcribed. Data analysis was completed through several readings of transcripts and main themes were derived by classifying, comparing, and contrasting coding. As a result of the study, the calculator played a role the tool as the mediation to communicate and the challenge their solvable tasks beyond the limitation of paper and pencil environments. But, in using the calculator, there was differences in gender between boys and girls. Above all, to enter commands into the calculator resulted in obstacles for learning process.