You are downloading the MateApp AppX file v184.108.40.206 for Windows Phone. MateApp is a free and useful Education app: New Version 220.127.116.11! Totally redesigned and redrawn screen for greater smoothness. Improved stability and performance of the calculation ... You can now download the offline AppX file to install & try it.
Download Locations for MateApp 18.104.22.168 AppX file
Important Notice: Now Due To Unspecified Limitations, You Can Not Use The Offline AppX File To Install It Any More.
To try to install it manually from an SD card, you should choose one of the server location above to get the offline MateApp AppX file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.