I installed the Sage backend for Cantor for both my laptop and Raspberry Pi 2. However, I do not see the Sage backend as an option when I open up Cantor.

However, I did get the Minecraft Pi commands to work in Cantor on the Raspberry Pi 2 with the Python 2 and Python 3 backends. So that’s a plus.

I figured it out.

On my laptop, I simply followed the directions at SageMath - Download for Linux

apt-add-repository -y ppa:aims/sagemath

apt-get update

apt-get install sagemath-upstream-binary

After Sage Math was installed, the backend showed up in Cantor.

On the Raspberry Pi, I had already installed the Sage compiled by Archimedes Pi. However, I had to point Cantor to it. To do that, go to Settings and choose Configure Cantor. Then click Sage on the left side and click the folder to Path to Sage and find the sage prompt in the sage-linux-armf-whatever-it-is folder in the sage-math folder.

Not the folder is not called sage-linux-armf-whatever-it-is, but I forgot exactly what it was called.