I'm not sure how it would work for knowledge that cannot be so easily represented as A=B.

More cards. You can think of of such knowledge as simply having more facts - this is the old code/data tradeoff. (For example, multiplication can be an algorithm - or, it's an infinitely large category of facts, such as 1x1=1, 1x2=2, 1x3=3...)

In practice, right now you would have to generate a large set of cards, but in the future SRS software will support cards which are programs; then it would be much easier to learn multiplication, say, or anything you could program (like Go life and death problems); see my comment on Reddit or look through mnemosyne-proj-users for my musings on the subject.