(Is That Correct?) In a handful of American schools, first-graders are discovering math and science -- in Japanese

"YON-BUN NO SAN" (THREE-fourths), says the eager second-grader as he holds up a card with the fraction spelled out in Japanese hiragana script and numerals. Then a classmate selects a segmented triangle that illustrates the fraction. "Atte imasuka?" (Is that correct?) asks the teacher from Tokyo. "Hai," says the class in unison as little hands go up to answer the next question.

This is a perfectly normal morning math class for 31 seven- and eight-year- olds in a room filled with typical Japanese elementary school wall charts. The only odd thing is, it's not in Tokyo. It's in Great Falls, Va.,...