They're both British kids shows that aired on Nickelodeon in the States. The Magic Roundabout was adapted into a CGI film a few years ago that was in turn redubbed for American audiences as "Doogal", maybe there's a chance you've heard of that?
I love that episode myself, ever since I first saw it. It's one of the funniest Jean episodes IMO and Homer's well characterized. Girls Just Want to Have Sums is just sort of bland and dumb for me, probably not the worst though.
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