I installed sage on ubuntu but nothing on the command line executes. The relevant portion in the long error message is:

ImportError: libgfortran.so.3: cannot open shared object file: No such file or directory

Error importing ipy_profile_sage - perhaps you should run %upgrade?

WARNING: Loading of ipy_profile_sage failed.

I tried sudo apt-get install gfortran and sudo apt-get install libgfortran.so.3

But neither seem to work. I tried the Ubuntu Software Center GUI but it seems broken as it keeps showing the rotating wait prompt even though my net is working. I'm a bit stuck. Thanks.