Supporting critical thinking in sequences and series through a problem-solving e-module with algebraic tasks
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Abstract
Examining sequences and series often leads students to rely on formulas, especially when assignments require algebraic modeling and generalization. This condition may hinder the advancement of critical thinking, especially in evaluation, inference, and reasoning. This study examined the extent to which a problem-solving e-module with algebraic challenges enhanced students' critical thinking and identified the elements that best facilitated critical thinking during the learning process. The study used a sequential explanatory mixed-methods design. The quantitative phase encompassed 89 senior high school students from three classes. Students completed a pretest, engaged with an e-module featuring guiding questions, scaffolding, feedback, and reflection, and then completed a posttest. The quantitative data were examined utilizing descriptive statistics, normalized gain, pretest-posttest comparisons, and effect size analysis. Data were gathered from students' e-module assignments, classroom observations, written reflections, and task-oriented interviews. The data were examined using theme coding and synthesized with the quantitative results. The results indicated an improvement in overall critical thinking and across all metrics; however, the improvements were inconsistent. Evaluation and interpretation improved more significantly than explanation. Feedback, directed inquiries, scaffolding, and reflection facilitated critical thinking; however, argument quality and algebraic reasoning varied among students.
INTRODUCTION
Students sometimes have difficulties with sequences and series when assignments require algebraic modeling(Kertil et al., 2019; Lee & Lee, 2021). A significant number of students can extend a pattern for the initial terms but find it challenging to accurately formulate the nth-term expression(Patterson & McGraw, 2018; Susanta et al., 2023; Wilkie, 2020). Students frequently confuse recursive rules with explicit forms, especially when assignments require conversion between the two(Sandefur & Manaster, 2022). In contextual concerns, students often misconstrue the given information, resulting in the creation of algebraic relationships that do not align with the actual scenario(Scheiner & Pinto, 2019). Errors in algebraic manipulation occur when students simplify expressions, formulate equations, or manage parameters(Soneira et al., 2018). Mathematical nomenclature, encompassing sigma notation and indices, often leads to inaccuracies(Yoon & Thompson, 2020). These problems undermine the quality of students' solutions and hinder their ability to provide logical justification.
Previous studies suggest that difficulties in sequences and series often arise from problems associated with generalization(Yao, 2022)and representation(Elia, 2020). Research on secondary school students shown heterogeneity in their levels of representation while articulating sequences, ranging from unstructured to fully ordered forms, and indicated that generalization strategies changed when tasks required extensive generalization(Yao, 2022). In close generalization, students mostly employed counting and addition operations, whereas in far generalization, strategies diversified, with correspondence methods emerging as the most common(Melhuish et al., 2020). Further research has highlighted pedagogical obstacles and the gap between knowledge obtained in secondary education and that necessary for higher education, leading students to depend on rote memorization of formulas and struggle with the transition between empirical and theoretical frameworks(Kop et al., 2020). A quasi-experimental study on numerical patterns in Singapore revealed that computational activity-based interventions did not consistently produce significant overall improvement; however, some students demonstrated substantial progress, suggesting that learning outcomes are greatly affected by the design of activities and the quality of instructional support(Vicente et al., 2022). These findings indicate that education should emphasize how students develop overarching principles, select strategies, and verify outcomes, rather than only rehearsing the application of formulas.
These issues have necessitated the implementation of teaching practices designed to improve critical thinking. Problem-solving instruction enables students to understand obstacles, formulate strategies, execute those methods, and assess their results(Voica et al., 2020). Problem-based(Xin et al., 2020)and inquiry-based learning(Pedersen & Haavold, 2023)require students to explain rationales, evaluate facts, and justify their strategic choices. In educational contexts, leading questions are often utilized to stimulate interpretation, analysis, and reasoning rather than just obtaining definitive answers(Foster et al., 2022). Scaffolding and metacognitive queries are employed to aid students in tracking their progress, recognizing faults, and enhancing their strategies(Çakmak Gürel, 2025). Delivering this support consistently, however, is difficult in conventional media. Printed worksheets fix a single solution path and cannot adapt prompts to a student's response; whole-class discussion distributes scaffolding unevenly and leaves little trace of individual reasoning; and video or static presentations convey content without eliciting or recording students' own justifications. An e-module addresses these constraints directly: it can sequence graduated tasks, embed guiding questions and scaffolding at the point of need, deliver staged feedback tied to reasoning rather than to final answers alone, and capture the process traces through which critical thinking becomes observable(Swidan et al., 2022). This last affordance is not merely convenient but methodologically necessary here, since analyzing which features elicit which critical thinking indicators during task performance (RQ2) requires a medium that records students' step-by-step interaction—data that conventional media do not provide. Such designs are expected to shift learning from mechanical formula application to analytical decision-making.
These strategies, however, share a limitation that constrains their capacity to promote critical thinking reliably: they attend to the products of student work rather than to the reasoning that generates them. Routine assessments reward procedural accuracy while leaving students' analysis and evaluation of strategies unexamined(Shaughnessy et al., 2019); where classroom discussion does occur, it is rarely anchored to explicit, measurable critical thinking criteria(Llinares, 2019); and e-modules are frequently reduced to digital worksheets that let students reproduce worked examples without constructing justifications(Amelia et al., 2026; Hidayat et al., 2025; Johar et al., 2025; Martin et al., 2021; Utami et al., 2018). The same product orientation recurs in how these approaches give feedback, which privileges the final answer over the quality of reasoning, the soundness of the method, and the plausibility of the result, and in how they are evaluated, typically stopping at pretest–posttest scores without documenting how students' cognitive processes change. This orientation also obscures an inconsistency in the evidence itself: even interventions that report positive effects do so unevenly, with substantial gains confined to only a subset of students(Vicente et al., 2022), yet without process-level data such divergent outcomes cannot be traced to the design features that drive them. Across otherwise different media and designs, then, the recurring gap is the absence of process-level evidence. This is why reported gains remain difficult to explain, and why the contribution of any specific design feature to those gains stays unidentified—the unresolved issue this study sets out to address.
This situation underscores the need for algebra-centric problem-solving activities that intentionally stimulate indicators of critical thinking. Assignments must require students to convert
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Amelia, R., Herman, T., Dasari, D., & Jupri, A. (2026). E-Miracle: An inquiry-realistic digital module to support students’ 6C competencies. Infinity Journal, 15(2), 483–508. https://doi.org/10.22460/infinity.v15i2.p483-508
Ayalon, M., & Wilkie, K. J. (2020). Investigating peer-assessment strategies for mathematics pre-service teacher learning on formative assessment. Journal of Mathematics Teacher Education, 24(4), 399–426. https://doi.org/10.1007/s10857-020-09465-1
Blanton, M., Isler-Baykal, I., Stroud, R., Stephens, A., Knuth, E., & Gardiner, A. M. (2019). Growth in children’s understanding of generalizing and representing mathematical structure and relationships. Educational Studies in Mathematics, 102(2), 193–219. https://doi.org/10.1007/s10649-019-09894-7
Çakmak Gürel, Z. (2025). Indication of scaffolding in mathematical modeling. International Journal of Science and Mathematics Education, 23(7), 2597–2628. https://doi.org/10.1007/s10763-025-10576-5
Çekmez, E. (2020). What generalizations do students achieve with respect to trigonometric functions in the transition from angles in degrees to real numbers? The Journal of Mathematical Behavior, 58, 100778. https://doi.org/10.1016/j.jmathb.2020.100778
Chorney, S., Evans, K. R., & Staples, M. (2024). Conceptualizing reasoning practices in the context of sociomathematical issues. The Journal of Mathematical Behavior, 73, 101124. https://doi.org/10.1016/j.jmathb.2024.101124
DiNapoli, J., & Miller, E. K. (2022). Recognizing, supporting, and improving student perseverance in mathematical problem-solving: The role of conceptual thinking scaffolds. The Journal of Mathematical Behavior, 66, 100965. https://doi.org/10.1016/j.jmathb.2022.100965
El Mouhayar, R. (2018). Trends of progression of student level of reasoning and generalization in numerical and figural reasoning approaches in pattern generalization. Educational Studies in Mathematics, 99(1), 89–107. https://doi.org/10.1007/s10649-018-9821-8
Elia, I. (2020). Word problem solving and pictorial representations: Insights from an exploratory study in kindergarten. ZDM – Mathematics Education, 52(1), 17–31. https://doi.org/10.1007/s11858-019-01113-0
Foster, C., Woodhead, S., Barton, C., & Clark-Wilson, A. (2022). School students’ confidence when answering diagnostic questions online. Educational Studies in Mathematics, 109(3), 491–521. https://doi.org/10.1007/s10649-021-10084-7
Hadar, L. L., & Ruby, T. L. (2019). Cognitive opportunities in textbooks: the cases of grade four and eight textbooks in Israel. Mathematical thinking and learning, 21(1), 54–77. https://doi.org/10.1080/10986065.2019.1564968
Hidayat, W., Aripin, U., & Widodo, S. A. (2025). Integration of ethno-modelling and 3N: An innovative digital worksheet framework to enhance students' mathematical critical thinking skills. Infinity Journal, 14(4), 1019–1042. https://doi.org/10.22460/infinity.v14i4.p1019-1042
Huang, R., Zhang, Q., Chang, Y.-p., & Kimmins, D. (2019). Developing students’ ability to solve word problems through learning trajectory-based and variation task-informed instruction. ZDM – Mathematics Education, 51(1), 169–181. https://doi.org/10.1007/s11858-018-0983-8
Johar, R., Annisa, D., Mailizar, M., Zubainur, C. M., Zubaidah, T., Usman, U., Indriyani, L., & Musa, M. (2025). Development of algebraic expressions e-modules through realistic mathematics education approach. Infinity Journal, 14(4), 973–994. https://doi.org/10.22460/infinity.v14i4.p973-994
Kertil, M., Erbas, A. K., & Cetinkaya, B. (2019). Developing prospective teachers’ covariational reasoning through a model development sequence. Mathematical thinking and learning, 21(3), 207–233. https://doi.org/10.1080/10986065.2019.1576001
Kim, N. J., Vicentini, C. R., & Belland, B. R. (2022). Influence of scaffolding on information literacy and argumentation skills in virtual field trips and problem-based learning for scientific problem solving. International Journal of Science and Mathematics Education, 20(2), 215–236. https://doi.org/10.1007/s10763-020-10145-y
Klein, S., & Leikin, R. (2020). Opening mathematical problems for posing open mathematical tasks: what do teachers do and feel? Educational Studies in Mathematics, 105(3), 349–365. https://doi.org/10.1007/s10649-020-09983-y
Kontorovich, I. (2021). Minding mathematicians’ discourses in investigations of their feedback on students’ proofs: a case study. Educational Studies in Mathematics, 107(2), 213–234. https://doi.org/10.1007/s10649-021-10035-2
Kop, P. M. G. M., Janssen, F. J. J. M., Drijvers, P. H. M., & van Driel, J. H. (2020). The relation between graphing formulas by hand and students’ symbol sense. Educational Studies in Mathematics, 105(2), 137–161. https://doi.org/10.1007/s10649-020-09970-3
Lee, H. S., Sanei, H., Famularo, L., Masters, J., Bradshaw, L., & Schellman, M. (2023). Validating a concept inventory for measuring students’ probabilistic reasoning: The case of reasoning within the context of a raffle. The Journal of Mathematical Behavior, 71, 101081. https://doi.org/10.1016/j.jmathb.2023.101081
Lee, M. Y., & Lee, J.-E. (2021). Pre-service teachers’ selection, interpretation, and sequence of fraction examples. International Journal of Science and Mathematics Education, 19(3), 539–558. https://doi.org/10.1007/s10763-020-10062-0
Lehmann, T. H. (2023). Using algorithmic thinking to design algorithms: The case of critical path analysis. The Journal of Mathematical Behavior, 71, 101079. https://doi.org/10.1016/j.jmathb.2023.101079
Leiss, D., Plath, J., & Schwippert, K. (2019). Language and mathematics - Key factors influencing the comprehension process in reality-based tasks. Mathematical thinking and learning, 21(2), 131–153. https://doi.org/10.1080/10986065.2019.1570835
Li, R., Cevikbas, M., & Kaiser, G. (2024). Mathematics teachers’ beliefs about their roles in teaching mathematics: orchestrating scaffolding in cooperative learning. Educational Studies in Mathematics, 117(3), 357–377. https://doi.org/10.1007/s10649-024-10359-9
Llinares, S. (2019). What mathematics teachers do and know: looks from inside and outside of the classroom to the mathematic-specificity of teacher work. Journal of Mathematics Teacher Education, 22(3), 227–230. https://doi.org/10.1007/s10857-019-09435-2
Martin, M., Syamsuri, S., Pujiastuti, H., & Hendrayana, A. (2021). Pengembangan e-modul berbasis pendekatan contextual teaching and learning pada materi barisan dan deret untuk meningkatkan minat belajar siswa SMP [Development of an e-module on sequences and series, based on the contextual teaching and learning approach, to enhance junior high school students' interest in learning]. Jurnal Derivat: Jurnal Matematika dan Pendidikan Matematika, 8(2), 72–87. https://doi.org/10.31316/j.derivat.v8i2.1927
Mata-Pereira, J., & da Ponte, J.-P. (2017). Enhancing students’ mathematical reasoning in the classroom: teacher actions facilitating generalization and justification. Educational Studies in Mathematics, 96(2), 169–186. https://doi.org/10.1007/s10649-017-9773-4
Melhuish, K., Thanheiser, E., & Guyot, L. (2020). Elementary school teachers’ noticing of essential mathematical reasoning forms: justification and generalization. Journal of Mathematics Teacher Education, 23(1), 35–67. https://doi.org/10.1007/s10857-018-9408-4
Patterson, C. L., & McGraw, R. (2018). When time is an implicit variable: An investigation of students’ ways of understanding graphing tasks. Mathematical thinking and learning, 20(4), 295–323. https://doi.org/10.1080/10986065.2018.1509421
Pedersen, I. F., & Haavold, P. Ø. (2023). Students’ mathematical beliefs and motivation in the context of inquiry-based mathematics teaching. International Journal of Mathematical Education in Science and Technology, 54(8), 1649–1663. https://doi.org/10.1080/0020739x.2023.2189171
Rezat, S., Malik, S., & Leifeld, M. (2022). Scaffolding close reading of mathematical text in pre-service primary teacher education at the tertiary level: Design and evaluation. International Journal of Science and Mathematics Education, 20(S1), 215–236. https://doi.org/10.1007/s10763-022-10309-y
Sandefur, J., & Manaster, A. B. (2022). Encouraging research on recursive thinking through the lens of a model of the spread of contagious diseases. ZDM – Mathematics Education, 54(4), 895–907. https://doi.org/10.1007/s11858-022-01354-6
Scheibling-Sève, C., Pasquinelli, E., & Sander, E. (2020). Assessing conceptual knowledge through solving arithmetic word problems. Educational Studies in Mathematics, 103(3), 293–311. https://doi.org/10.1007/s10649-020-09938-3
Scheiner, T., & Pinto, M. M. F. (2019). Emerging perspectives in mathematical cognition: Contextualizing, complementizing, and complexifying. Educational Studies in Mathematics, 101(3), 357–372. https://doi.org/10.1007/s10649-019-9879-y
Shaughnessy, M., Boerst, T. A., & Farmer, S. O. (2019). Complementary assessments of prospective teachers’ skill with eliciting student thinking. Journal of Mathematics Teacher Education, 22(6), 607–638. https://doi.org/10.1007/s10857-018-9402-x
Soneira, C., González-Calero, J. A., & Arnau, D. (2018). An assessment of the sources of the reversal error through classic and new variables. Educational Studies in Mathematics, 99(1), 43–56. https://doi.org/10.1007/s10649-018-9828-1
Susanta, A., Sumardi, H., Susanto, E., & Retnawati, H. (2023). Mathematics literacy task on number pattern using Bengkulu context for junior high school students. Journal on Mathematics Education, 14(1), 85–102. https://doi.org/10.22342/jme.v14i1.pp85-102
Swidan, O., Bagossi, S., Beltramino, S., & Arzarello, F. (2022). Adaptive instruction strategies to foster covariational reasoning in a digitally rich environment. The Journal of Mathematical Behavior, 66, 100961. https://doi.org/10.1016/j.jmathb.2022.100961
Toulmin, S. E. (2003). The uses of argument (2 ed.). Cambridge University Press. https://doi.org/DOI: 10.1017/CBO9780511840005
Utami, T. N., Jatmiko, A., & Suherman, S. (2018). Pengembangan modul matematika dengan pendekatan science, technology, engineering, and mathematics (STEM) pada materi segiempat [Development of a mathematics module using the science, technology, engineering, and mathematics (STEM) approach for the topic of quadrilaterals]. Desimal: Jurnal Matematika, 1(2), 165–172. https://doi.org/10.24042/djm.v1i2.2388
Vicente, S., Verschaffel, L., Sánchez, R., & Múñez, D. (2022). Arithmetic word problem solving: Analysis of Singaporean and Spanish textbooks. Educational Studies in Mathematics, 111(3), 375–397. https://doi.org/10.1007/s10649-022-10169-x
Voica, C., Singer, F. M., & Stan, E. (2020). How are motivation and self-efficacy interacting in problem-solving and problem-posing? Educational Studies in Mathematics, 105(3), 487–517. https://doi.org/10.1007/s10649-020-10005-0
Wilkie, K. J. (2020). Investigating students’ attention to covariation features of their constructed graphs in a figural pattern generalisation context. International Journal of Science and Mathematics Education, 18(2), 315–336. https://doi.org/10.1007/s10763-019-09955-6
Wilkie, K. J. (2021). Seeing quadratics in a new light: secondary mathematics pre-service teachers’ creation of figural growing patterns. Educational Studies in Mathematics, 106(1), 91–116. https://doi.org/10.1007/s10649-020-09997-6
Xin, Y. P., Park, J. Y., Tzur, R., & Si, L. (2020). The impact of a conceptual model-based mathematics computer tutor on multiplicative reasoning and problem-solving of students with learning disabilities. The Journal of Mathematical Behavior, 58, 100762. https://doi.org/10.1016/j.jmathb.2020.100762
Yao, X. (2020). Unpacking learner’s growth in geometric understanding when solving problems in a dynamic geometry environment: Coordinating two frames. The Journal of Mathematical Behavior, 60, 100803. https://doi.org/10.1016/j.jmathb.2020.100803
Yao, X. (2022). Representation transformations in transition from empirical to structural generalization. The Journal of Mathematical Behavior, 66, 100964. https://doi.org/10.1016/j.jmathb.2022.100964
Yasin, M., Jauhariyah, D., Madiyo, M., Rahmawati, R., Farid, F., Irwandani, I., & Mardana, F. F. (2019). The guided inquiry to improve students mathematical critical thinking skills using student’s worksheet. Journal for the Education of Gifted Young Scientists, 7(4), 1345–1360. https://doi.org/10.17478/jegys.598422
Yoon, H., & Thompson, P. W. (2020). Secondary teachers’ meanings for function notation in the United States and South Korea. The Journal of Mathematical Behavior, 60, 100804. https://doi.org/10.1016/j.jmathb.2020.100804
Zimmerman, B. J. (2002). Becoming a self-regulated learner: An overview. Theory Into Practice, 41(2), 64–70. https://doi.org/10.1207/s15430421tip4102_2