You can check what kind of mobile phone software you have in the App Store. You can try to download a math plus software. If you don't like it, you can directly search in the application treasure and it will come out. As long as you search for the key words of the senior high school entrance examination, there will be many, such as what is necessary for the senior high school entrance examination and what you want to learn. These softwares will not affect mobile phones, so you can download and use them with confidence.