You are downloading the 21 Math Card XAP file v220.127.116.11 for Windows Phone. 21 Math Card is a free and fun Educational game: This is an intelligence game. In 5 or 4 cards try to find a combination of 21. It's not only for kid's arithmetic practice, but also a good ... You can now download the offline XAP file to install & try it.
Download Locations for 21 Math Card 18.104.22.168 XAP file
Important Notice: Now Due To Unspecified Limitations, You Can Not Use The Offline XAP 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 21 Math Card XAP file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.