This study aims to analyze the implementation of computational estimation in the 3rd and 4th-grade mathematics textbooks for natural number operations, based on the 2022 Revised Mathematics Curriculum. For this purpose, nine types of state-authorized textbooks were analyzed. Estimation tasks were categorized into three types: Type A, which involves comparing estimated values with exact calculated values; Type B, which requires only estimation; and Type S, which is classified based on whether estimation strategies are explicitly presented. Furthermore, Type B tasks were sub-divided into specific types (CJ, QE, RJ) for in-depth analysis, and the types and methods of the presented estimation strategies were examined.
The results revealed that in the 3rd and 4th-grade textbooks, computational estimation is primarily utilized as a supplementary activity to verify calculation results. While there were variations in the presentation of tasks requiring only estimation (Type B) across different textbooks and sub-types, their overall proportion remained low. Most of the estimation strategies provided were "Quasi-exact" strategies, predominantly presented through indirect methods such as speech bubbles. These findings suggest the need for textbooks to enrich contexts where estimation is essential by incorporating diverse types of estimation-only problems. Additionally, it highlights the necessity of diversifying both the strategies and the methods of presentation for computational estimation.