Hey I know there are no. of Apps which are exclusive for windows phone but I found a very good app for math lovers, which is not yet available for android, they released for iPhone & windows phone & for android it will be coming soon, so something to cheer about my windows!!
Here it is:-
https://photomath.net/
http://www.windowsphone.com/en-us/store/app/photomath/1f25d5bd-9e38-43f2-a507-a8bccc36f2e6
Here it is:-
https://photomath.net/
http://www.windowsphone.com/en-us/store/app/photomath/1f25d5bd-9e38-43f2-a507-a8bccc36f2e6