These are basic lessons which were designed for teaching at secondary school level. These are not meant to by in-depth materials and were only intended for key stage 3 and key stage 4 students. These are based on the national curriculum taught in the United Kingdom. These notes can, however, be used in a variety of situation. I have listed all the articles in order as these were taught. You can read it in any order you like.
Here are some of the links.