Noor Rita Syofiyawati, Gunarhadi. Improving Mathematic Learning Achievement Using Abacus Counting Tool for Down Syndrome Children in The 3rd Grade of SLBP Putra Harapan Gondang Sragen, Central Java, Indonesia in The School Year Of 2015/2016. IJEPC [Internet]. 2024 Sep. 24 [cited 2025 Oct. 21];2(3). Available from: https://gaexcellence.com/ijepc/article/view/2757