What have i learnt in chapter 2.1?

I have learnt to change the signs when needed and how to find the answers. I learnt to answer the questions by placing all the same algebric expression together and then simplify it. By doing this i would not confuse myself anymore. I also learnt where to place the brakets in order to get the answer correct.Doing it step by step also helps me break down the question and make it easier for me to do.