Unit 5 (2nd ESO): Algebra
Video 1: Why Learn Algebra? https://www.youtube.com/watch?v=eD2hLhhYmbg
Video 2: Basic Algebra Part I :https://www.youtube.com/watch?v=APM8TQzL1LA
Video 3: Basic Algebra Part II: https://www.youtube.com/watch?v=_QeX7wqBNTA
Video 4: Introduction to Variables: https://www.youtube.com/watch?v=fdzrf_EZrM8&list=PLIsh0ZctUC41IrOyqszVmaKGpXnwNyuC8