According to the Japanese Wikipedia article I cited above, children were not taught that pi equals 3; rather, children who had not yet learned how to calculate

According to the Japanese Wikipedia article I cited above, children were not taught that pi equals 3; rather, children who had not yet learned how to calculate with decimals were told that they could use 3 as a rough approximation for pi when calculating by hand. This minor change in the official curriculum came at a time when the Japanese government was trying to de-emphasize rote memorization and promote critical thinking in school education. Because that policy also reduced class hours and the amount of material covered, it was widely criticized for supposedly dumbing down school education. The notion that children were being taught “pi = 3” was an exaggeration, but it resonated with other objections to educational policy and apparently led the university to pose that problem on its entrance exam in protest. I still think it's an interesting problem. I wonder how far I could have gotten with it if, at the age of 18 or 19, I had encountered it on an exam and had just twenty or thirty minutes to try to come up with a proof.