Kindergarten, which is German for "children's garden," is serious stuff these days. With half-day programs giving way to full days in state after state, the curriculum once saved for first grade has been pushed down to 5- and 6-year-olds.
Elementary school educators across the country, not to mention members of Congress and the president of the United States, are trying to inject words into seemingly every moment of every 6-year-old's life.
Once it was a time for youngsters to master reading and math skills learned in first grade and prepare for the independent learning traditionally demanded in third grade. But in many public schools across the country, second grade has moved on.
These days, everything starts with third grade. It is the first year in which states test students in reading and math under the No Child Left Behind law. Many schools have reorganized to make sure those 8- and 9-year-olds get all the attention they need.
Fourth-graders have left behind the primary years and entered an intermediate stage seen as a transition to middle school.
Fifth-graders often learn rapidly and are capable of advanced academic work, and yet they are also as fun-loving and genuine as when school was new and they were just learning to read.
Sixth grade is a weird year, full of physical, emotional, social and logistical transitions that schools meet with wildly varying levels of success.
For two decades, policymakers have decreed that seventh grade should be a time when children have a chance to adjust to puberty and cliques and the other annoyances of turning 13. Now that attitude is changing.
Once stuck squarely in the middle of junior high, eighth grade has taken on new importance as the end of the modern middle-school experience. It is the gateway to the super-charged, high-school world.
Teachers are increasingly searching the records of each new ninth-grader before school begins and talking to their families and previous teachers.
Once less fraught than the earnest freshman year before it and the intense junior year that follows, 10th grade now pulses with a tension of its own.
No single grade in the K-12 system produces more reports of anxiety and stress than 11th grade.
As national concern grows over the quality of America's workforce -- and with reports that about 30 percent of students who go to college need remediation -- 12th grade has become a central issue in the debate about the future of public education.