Raspbian Jessie and Wheezy distribution includes Wolfram Language and Mathematica. While this can be helpful for students, it doesn’t have much use for others. The following instructions will remove both Wolfram and Mathematica from your Raspberry Pi (Raspbian distribution). It saves 658MB in Jessie.

sudo apt-get remove wolfram-engine
Reading package lists... Done
Building dependency tree 
Reading state information... Done
The following packages will be REMOVED:
 wolfram-engine
0 upgraded, 0 newly installed, 1 to remove and 59 not upgraded.
After this operation, 658 MB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 150191 files and directories currently installed.)
Removing wolfram-engine (10.3.1+2016012407) ...
Processing triggers for man-db (2.7.0.2-5) ...
Processing triggers for gnome-menus (3.13.3-6) ...
Processing triggers for desktop-file-utils (0.22-1) ...
Processing triggers for mime-support (3.58) ...
Processing triggers for shared-mime-info (1.3-1) ...
Processing triggers for hicolor-icon-theme (0.13-1) ...

Then there is one final step:

sudo rm /usr/share/raspi-ui-overrides/applications/wolfram-language.desktop /usr/share/raspi-ui-overrides/applications/wolfram-mathematica.desktop

And you are done!

PS. You can read more about these free (not for commercial use) packages here.