1. Akkaya, R. (2016). An Investigation into the Number Sense Performance of Secondary School Students in Turkey. Journal of Education and Training Studies, 4(2), 113-123.
2. Amalina K., Fuad Y. & Agustina I. D. (2018). Fraction Magnitude Knowledge: Students Strategy in Estimating Fractions. Journal of Physic. doi :10.1088/1742-6596/1108/1/012058
3. Bailey D. H., Zhou X., Zhang Y., Cui J., Fuchs L. S., Jordan N. C., Gersten R. & Siegler R. S.. (2015). A Development of fraction concepts and procedures in U.S. and Chinese children. Journal of Experimental Child Psychology, 129,68–83
4. Bailey, D. H. et al. (2014). Development of fraction concepts and procedures in U.S. and Chinese children. Journal of Experimental Child Psychology, 129(2015), 68-83.
5. Byerley, C. (2019). Calculus students’ fraction and measure schemes and implications for teaching rate of change functions conceptually. Journal of Mathematical Behavior, 55(2019), 100694.
6. DeWolf, M., Bassok, M., & Holyoak, K. J. (2015). From rational numbers to algebra: Separable contributions of decimal magnitude and relational understanding of fractions. Journal of Experimental Child Psychology, 133, 72-84.
7. Fazio L. K., Kennedy C. A., Siegler R. S. (2016). Improving Children’s Knowledge of Fraction Magnitudes. PLoS ONE 11(10): e0165243. doi:10.1371/journal.pone.0165243
8. Fuchs, L. S., Schumacher, R. F., Long, J., Namkung, J., Hamlett, C. L., Cirino, P. T. (2013). Improving at-risk Learners’ Understanding of Fractions. Journal of Educational Psychology, 105(3), 683.
9. Gersten R. M., Schumacher R. F. & Jordan N. C. (2016). Life on the Number Line: Routes to Understanding Fraction Magnitude for Students With Difficulties Learning Mathematics. Journal of Learning Disabilities. 50. 10.1177/0022219416662625.
10. Hecht, S. A., & Vagi, K.J. (2011). Patterns of strengths and weaknesses in children’s knowledge about fractions. Journal of Experimental Child Psychology, 111(2012), 212-229.
11. Kor, L. K., Teoh, S. H., Mohamed, S. S. E. & Singh, P. (2019). Learning to Make Sense of Fractions: Some Insights from the Malaysian Primary 4 Pupils. International Electronic Journal Of Mathematics Education, 14(1). https://doi.org/10.29333/iejme/3985
12. Lortie-Forgues, H., Tian, J. & Siegler, R. S. (2015). Why is learning fraction and decimal arithmetic so difficult? Developmental Review, 38. http://dx.doi.org/10.1016/j.dr.2015.07.008
13. Maghfirah, M. & Mahmudi, A. (2018). Number sense: the result of mathematical experience. Journal of Physics: Conference Series. doi :10.1088/1742-6596/1097/1/012141
14. Merritt, D. J., DeWind, N. K., & Brannon, E. M. (2012). Comparative cognition of number representation. In T. R. Zentall & E. A. Wasserman (Eds.), The Oxford handbook of comparative cognition (p. 451–476). Oxford University Press.
15. Ministry of Education Malaysia (2012). Kurikulum Bersepadu Sekolah Menengah: Spesifikasi Kurikulum Matematik Tingkatan 4. Bahagian Pembangunan Kurikulum.
16. Ministry of Education Malaysia. (2014). Kurikulum Standard Sekolah Rendah Dokumen Standard Kurikulum Dan Pentaksiran, Matematik Tahun Lima. Retrieved from http://bpk.moe.gov.my/index.php/terbitan-bpk/kurikulum-sekolah-rendah/category/7-dskp-tahun-5?download=180:matematik-sk
17. Ministry of Education Malaysia. (2014). Kurikulum Standard Sekolah Rendah Dokumen Standard Kurikulum Dan Pentaksiran, Matematik Tahun Enam. Retrieved from http://bpk.moe.gov.my/index.php/terbitan-bpk/kurikulum-sekolah-rendah/category/8-dskp-tahun-6?download=152:matematik-sk
18. Ministry of Education Malaysia. (2015). Kurikulum Standard Sekolah Rendah Dokumen Standard Kurikulum Dan Pentaksiran, Matematik Tahun Satu. Retrieved from http://bpk.moe.gov.my/index.php/terbitan-bpk/kurikulum-sekolah-rendah/category/47-dskp-tahun-1-semakan?download=2005:dskp-kssr-semakan-2017-matematik-tahun-1
19. Ministry of Education Malaysia. (2016). Kurikulum Standard Sekolah Rendah Dokumen Standard Kurikulum Dan Pentaksiran, Matematik Tahun Dua. Retrieved from http://bpk.moe.gov.my/index.php/terbitan-bpk/kurikulum-sekolah-rendah/category/42-dskp-tahun-2-semakan?download=2227:dskp-kssr-semakan-2017-matematik-tahun-2
20. Ministry of Education Malaysia. (2017). Kurikulum Standard Sekolah Rendah Dokumen Standard Kurikulum Dan Pentaksiran, Matematik Tahun Tiga. Retrieved from http://bpk.moe.gov.my/index.php/terbitan-bpk/kurikulum-sekolah-rendah/category/228-dskp-tahun-3?download=2038:dskp-kssr-semakan-2017-matematik-tahun-3
21. Ministry of Education Malaysia. (2018). Kurikulum Standard Sekolah Rendah Dokumen Standard Kurikulum Dan Pentaksiran, Matematik Tahun Empat. Retrieved from http://bpk.moe.gov.my/index.php/terbitan-bpk/kurikulum-sekolah-rendah/category/335-dskp-tahun-4?download=2876:dskp-kssr-semakan-2017-matematik-tahun-4
22. Mohamed, M., & Johnny, J. (2010). Investigating number sense among students. Procedia Social and Behavioral Sciences, 8(2010), 317-324.
23. Rezat, S. & Ejersbo, L. R. (2018). Number sense in teaching and learning arithmetic. In T. Dreyfus, M. Artigue, D. Potari, S. Prediger & K. Ruthven (Eds.), Developing Research in Mathematics Education: Twenty Years of Communication, Cooperation and Collaboration in Europe. Routledge.
24. Singh, P., Rahman, N. A., Ramly, M. A. & Hoon, T. S. (2019). From Nonsense to Number Sense: Enumeration of Numbers in Math Classroom Learning. The European Journal of Social and Behavioural Sciences, 25(2). https://dx.doi.org/10.15405/ejsbs.256
25. Torbeyns, J., Schneider, M., Xin, Z., & Siegler, R. S. (2014). Bridging the gap: Fraction understanding is central to mathematics achievement in students from three different continents. Learning and Instruction, 37(2015), 5-13.
26. Woods, D. & Geller, L. K. & Basaraba, D.. (2017). Number Sense on the Number Line. Intervention in School and Clinic.