During the school year 2017/2018 and 2018/2019, a Math teacher, Mrs. Marija Milovanović, used a social networking site – Facebook as a helping tool for teaching Mathematics - in the primary school "Branko Radičević" Sedlare, Serbia. The results were presented at eLearning Conference 2019 (Belgrade, Serbia, September 2019), where the initial contact with the LAMBDA project was created.