Below are a couple of interactive exercises that you can continue to attempt until you get the correct answer. The first one is very simple and for you to get accustomed to entering and checking answers. The second relates to the material in this section. Interactive elements such as these will be scattered throughout the text so that you can test your knowledge right away and at no cost for trying as many times as you like. To get the best result from these, try to avoid clicking on the provided solution unless you are hopelessly stuck.