Ahsan, Fikri Fathony. “The Effect of Numbered Heads Together (NHT) on Elementary School Students’ Mathematical Problem-Solving Ability in Geometry”. Mathline : Jurnal Matematika dan Pendidikan Matematika 10, no. 3 (August 12, 2025): 659–670. Accessed December 24, 2025. https://mathline.unwir.ac.id/index.php/Mathline/article/view/787.