Anggraini LN, Isrokatun I, Aeni AN. Development of grubi mathematics module to improve the ability to calculate the addition and subtraction of small numbers in grade 2 elementary students. Math Didactic [Internet]. 15 April 2023 [dikutip 16 Juli 2025];9(1):157-72. Tersedia pada: https://jurnal.stkipbjm.ac.id/index.php/math/article/view/2132