zulhendrik, Ambiyar, and Ishak Aziz. “THE ABILITY TO UNDERSTAND MATHEMATICAL CONCEPT OF STUDENTS OF CLASS VII SMPN 3 PEKANBARU THROUGH COOPERATIVE LEARNING MODEL TYPE OF GROUP INVESTIGATION”. International Journal Of Humanities Education and Social Sciences, vol. 1, no. 2, Oct. 2021, doi:10.55227/ijhess.v1i2.45.