*Result*: The reconstruction process of arithmetic sequence concept using microsoft excel for senior high school students.

*This article describes the author's best practices in implementing technology-assisted arithmetic sequence learning. The method used in this best practice is a qualitative method, which is to pay attention to or observe additional knowledge obtained by students from reconstructing the concept of arithmetic sequences. The target of implementing this best practice is 65 students in class X in semester 1 of the 2022-2023 school year at one of the State High Schools in Sidoarjo in two different classes. The first class was given the task of creating a simple program using Microsoft Excel related to the topic of arithmetic sequences. In contrast, the second class was given the task of analyzing the program. In both the first and second classes, in the preliminary activities, students can answer contextual problems without using the formula for determining the nth term of the arithmetic sequence. In the first class, there are nine groups. Two groups succeeded in making a simple program related to arithmetic sequences using Microsoft Excel, and the other seven groups can make programs but they are not yet applicable in general. These results show that the process of reconstructing the concept of arithmetic sequences using technology leads students not only to rediscover the concept of arithmetic sequences but also to create simple programs related to arithmetic sequences in Microsoft Excel. In the second class, there are nine groups; four groups can rediscover the general formula for determining the nth term, and the other five groups are constrained in addition operations in algebra. The error in algebraic operations occurs in the concept of addition, which is confused with the concept of multiplication. These results show that technology can be used for learning by constructing or reconstructing mathematical concepts. Thus, the process of reconstruction of technology-assisted knowledge can provide an additional "current" understanding of knowledge. [ABSTRACT FROM AUTHOR]*