Dear Readers and Authors of Kalamatika: Journal Pendidikan Matematika Our website could not be accessed due to disruption of Kalamatika's journal web from  2 to 8 December 2021. We apologise for the inconvenient. There have been disruptions to most hosting and VPS services belonging to our server provider in Jakarta, Indonesia. All published works for vol.  6 no. 2 2021 were gone temporarily since our latest back up data was only available before the publishing date (30 November 2021). At the moment we are still working to recover the data and we will republish the articles as soon as possible. The official statement from our server provider regarding the unavoided accident of the current event can be found in this link ( Once again, we apologise for the service disruptions that have occurred as a result of this incident. Best Wishes Krisna S. Perbowo Editor in Chief of Kalamatika: Jurnal Pendidikan Matematika ===================================================================