Hardani, R. N., and L. I. Rocmah. “Increasing The Ability To Recognize Number Symbols Through The Activities Of Playing Snakes And Stairs For Children Of Group A In Tk Aisyiyah Busthanul Athfal 6 Candi”. Academia Open, Vol. 5, Aug. 2021, p. 10.21070/acopen.5.2021.2221, doi:10.21070/acopen.5.2021.2221.