Mathematics education has been closely related to societal changes. Over the past few decades, mathematics curricula in major countries have been revised and influenced by each other with ongoing changes in mathematics education. In mathematics classes, there has been a shift away from the previously prevalent multiple-choice and rote memorization methods, towards enhancing problem-solving abilities and emphasizing logical thinking. Changes in teaching practices have also emerged, including mathematical communication and the integration of real-life applications outside the classroom. In this context, teachers’ classroom practices had to undergo substantial changes, and examining how teachers actually conduct their classes became a major topic of discussion in education. This study aims to highlight the characteristics of mathematics teaching activities by elementary school teachers in Korea and suggest directions for their development. To achieve this, the study utilized time-series data from TIMSS to compare the teaching activities of elementary teachers in Korea, the United States, and Singapore. The study identified that, in response to changes in the educational environment, Korean elementary school teachers have developed certain distinctive teaching activities compared to their counterparts in other TIMSS countries. Consequently, the study proposed support measures for teaching activities of Korean elementary school teachers’ classes, including the introduction of a specialized mathematics teacher to facilitate more professional teaching of Korean elementary schools.