Sapta, A., Pakpahan, S.P. and Sirait, S. 2019. Using The Problem Posing Learning Model Based On Open Ended To Improve Mathematical Critical Thinking Ability. Journal of Research in Mathematics Trends and Technology. 1, 1 (Mar. 2019), 12-15. DOI:https://doi.org/10.32734/jormtt.v1i1.752.