Square One TV, on PBS
IMDb; Retro Junk; TV.com; TV Tropes; Wikipedia

The point of this show was to teach math to kids. There were lots of funny sketches and songs and whatnot. And every episode would end with a Mathnet story (kinda like how every episode of 3-2-1 Contact would end with a "Bloodhound Gang" story). Anyway, I remember both Square One and Mathnet fondly, and still occasionally think of some of the songs and things from Square One. It's all very nostalgic to me.