Depends on which school, as this is not taught at all outside mathematics school. My claim is you can teach it to 5th graders, this is what I tell my university

Depends on which school, as this is not taught at all outside mathematics school. My claim is you can teach it to 5th graders, this is what I tell my university students and I mean it. Myself and others from the math schools knew this algorithm in 8th grade for sure, as we been already using it in 9th grade for competitions. This does not mean all my classmates knew it, of course not. So it depends who you teach this to. Theoretically - you should be able to, practically - well, perhaps not so much, as math is not the only thing 8th grader learns, in fact his head is bombarded with ... dozen disciplines at a time. Besides, I recently met a classmate, previous IoI medalist, who works quant-something somewhere for 15th + years, and is a PHD and everything. We start talking about mathematics and I find to my total surprise he knows very little about grammars, never used them. He remembers Dijkstra or Ford-Fulkerson, but only as a title, while I'm sure he learned these at some point in Stanford, as the shortest-path and A* was not something we had in textbooks back in the 90s for sure.