Numerical ability is very important to possess by students in learning mathematics. Increased numerical ability impacts learning outcomes. The purpose of this study was to determine the impact of the Two Stay-Two Stray learning model on the numerical ability of students on the sequence and series topics. The research method used was a quasi-experimental method with a post-test-only control design research design. The assessment instrument used the problem description. Based on the analysis of the post-test score by using a t-test of two uncorrelated samples obtained tobserved = 2.955>tcritical = 2.002 (α = 0.05) with an average post-test score of 81.6 in the experimental class and 76 in the control class. A significant result of numerical ability between the control class and the experimental class was found. It can be concluded that the Two-Stay Two-Stray model produced a greater post-test mean score than the conventional model.

This study aims to determine the mathematical reasoning ability and self-esteem of high school students in class XI in the science program in learning mathematics for the subject matter of linear programming. The type of research used is descriptive qualitative. The sample in this study was 20 students who would be given a test in the form of a description of five questions and a self-esteem questionnaire totaling twenty-six statements. Analysis of research data was carried out by analyzing the results of students' answers according to indicators of mathematical reasoning abilities and the results of the self-esteem questionnaire given. The results of the analysis of students' answers obtained research results that (1) based on the results of the analysis of each indicator include: (a) Presenting mathematical statements in the form of pictures or writing, (b) Proposing allegations, (c) Carrying out mathematical manipulations, (d) Drawing conclusions, (e) Arranging evidence and providing reasons and solutions, and (f) Checking the validity of the arguments, the results are that students' mathematical reasoning abilities are categorized as very low; and (2) self-esteem analysis of students is categorized as good. Based on the analysis, it was concluded that the reasoning ability and self-esteem of the students of SMA Negeri 1 Talang Padang in class XI of the Linear Program material were categorized as good