In the high desert around the capital city of Window Rock on the Navajo Nation, you will find a scene that has been common in Eastern Europe since the 1930s. Schoolchildren are gathered with heads bowed and pencils clutched, intently looking at math problems. They may be serious about the task at hand, but they also laugh, discuss, and debate a little before one steps to the board and lays out a problem — and an equation to solve it — in an exercise that demonstrates both technique and skill.