Development of the application to practice mathematical skills on a computer tablet for grade 1. Have been worked with the application development complete was implemented with the samples to find the effectiveness of tools. Collected information from the this trial to find the effectiveness of the statistical analysis. Application has been used to improve a group of students. The working process. The students pre-test to collect information. Upon completion, students take a post-test to data collection. The research instruments Application practice of mathematical skills, quality evaluation of the 3 aspects. Have good quality level average of 4.79 learning achievement before and after learning it was found that score after good learn than before. The significant 0.01 shows applications developed can be used to test the learning efficiency.