American Journal of Educational Research, 2019, Vol. 7, No. 11, 830-836 Available online at http://pubs.sciepub.com/education/7/11/12 Published by Science and Education Publishing DOI:10.12691/education-7-11-12 Differences in the Ability to Understand Mathematical Concepts of Students Taught by Using Guided Discovery Learning and Contextual Teaching and Learning Models Assisted by Autograph Software Viewed from Student Learning Styles Rosauli Novalina Samosir * , Pargaulan Siagian, Humuntal Banjarnahor Universitas Negeri Medan, Jalan Willem Iskandar Pasar V Medan Estate, Indonesia *Corresponding author: rosauli.novalina@yahoo.com Received September 19, 2019; Revised October 28, 2019; Accepted November 18, 2019 Abstract This study aims to determine (1) whether the ability to understand mathematical concepts of students taught by Guided Discovery Learning (GDL) assisted by Autograph Software is higher than students taught by Contextual Teaching and Learning (CTL) assisted by Autograph Software, (2) whether the ability students' understanding of mathematical concepts in the convergent learning style group is higher than that of the divergent learning style group. This type of research is a quasi-experimental study with a research population of all grade X students of Parulian 1 Medan Private High School. This study uses 2x2 two-way ANAVA. Then proceed with the t test to see whether the two groups differ significantly. Based on the t test statistical calculations and confirmed with spss, it can be concluded that (1) The ability to understand mathematical concepts of students taught by Guided Discovery Learning (GDL) assisted by Autograph Software is higher than students taught by Contextual Teaching and Learning (CTL) with Software Autograph, (2) The ability to understand students' mathematical concepts in the convergent learning style group is higher than that of the divergent learning style group. Keywords: contextual teaching and learning, guided discovery learning, concept understanding ability, autograph software Cite This Article: Rosauli Novalina Samosir, Pargaulan Siagian, and Humuntal Banjarnahor, “Differences in the Ability to Understand Mathematical Concepts of Students Taught by Using Guided Discovery Learning and Contextual Teaching and Learning Models Assisted by Autograph Software Viewed from Student Learning Styles.” American Journal of Educational Research, vol. 7, no. 11 (2019): 830-836. doi: 10.12691/education-7-11-12. 1. Introduction Understanding concepts is one of the basic abilities that is very important and must be possessed by every student in learning mathematics. Based on the 2013 Curriculum, one of the objectives of giving mathematics at the secondary school level is for students to understand mathematical concepts. Understanding mathematical concepts includes competence in explaining inter-concept interrelations and using concepts or algorithms flexibly, accurately, efficiently and precisely in problem solving, as in [1]. The importance of understanding the concept can also be seen from the statement of [2], that mathematical understanding is very important in learning mathematics because it will facilitate the solving of mathematical problems. Which, as said [3] that, each student must have a particular problem-solving abilities in solving problems or questions given by the teacher. Understanding the concept also acts as a bridge or link between the previous concept with the concept that will be studied in the next material. The importance of understanding other conceptual abilities was revealed by [4], that students who have a better understanding of mathematics will be able to compete in the economic world. The ability to understand concepts is very important to be developed in every student in the learning process. But in reality, mathematics learning does not involve optimal student activity in terms of increasing understanding of mathematical concepts. Factors that also need to be considered to improve student achievement, as in [5] that, classroom and school condition are viewed as essential factors to students achievement. Reference [6] that the Principal as a leader, a role leading the school in order to empower the school resources optimally, to be able to develop and implement the school’s vision and feel school as theirs. Good management of academic program focused on students’ success into learning process, began with planning, organizing, performing, controlling must depend on students’ learning necessessity, as in [7]. So, one way