The application has been prepared according to the textbook topics. Unlimited transactions dominate. The test part is less and when the question is made wrong in the activities, it does not pass to the new question. The aim is to make it done on purpose. Each section has a question solution video. Whenever you have a question about the subject, you can look. Clicking the video icon, wait 5-10 seconds and click the start button to open the video. The dimensions of the videos are low. The total size of all videos is 1 GB. When all of them are watched for 1 year, they only spend 1 GB of quota. Anyone can watch it on Youtube. The numbers in the sections written without limits change each time and can be made as desired.