The number and type of math classes needed to graduate depends on the high school. At some schools, for example, students are required to take math all four years of high school, even after they complete the minimum math requirements. Other schools allow students to skip math during their junior and senior years if they have finished their minimum requirements. Forty-five states have now implemented the Common Core standards, which help guide local math curricula. Only Nebraska, Texas, Alaska, Virginia and Minnesota have foregone Common Core, allowing local school boards to choose their curricula instead.

## Algebra

Algebra I and II are fundamental components of a high school math curriculum, and usually each takes one year to complete. Students who take Algebra I in middle school might begin high school in Algebra II or geometry, and take Algebra III or another advanced math class their senior year. Students who are unprepared for high school algebra might take a pre-algebra course their freshman year. Common Core makes Algebra I and II explicit requirements, but virtually all schools require some variety of algebra.

## Geometry

The Common Core standards strongly emphasize geometry. Most students take geometry during their freshman or sophomore year of high school, and high school geometry classes have a strong emphasis on trigonometry. In some states, such as Alabama, geometry is so central to the curriculum that it's tested on a high school exit exam. Even in states that do not use Common Core standards, geometry remains an integral part of the curriculum.

## Statistics and Probability

The Common Core standards require that students learn the basics of statistics and probability as part of their math curriculum. At some schools, statistics and probability are integrated into algebra and geometry classes, while in other schools, students are required to take an independent statistics and probability course. For example, at St. Pius X, a private high school in Atlanta, students who don't qualify for Advanced Placement or honors classes -- courses that incorporate statistics into algebra and geometry -- take statistics their senior year.

## Other Courses

Some school systems require students to take a fourth math class if they complete other graduation requirements prior to their senior year. In Arizona public schools, for example, students who have completed Algebra I and II and geometry must complete an additional class approved by local school boards. This might be an Advanced Placement class in calculus for high-performing students, or it could be a class such as discrete math or pre-calculus. In California public schools, by contrast, students are required to take only two years of math, so those who finish core requirements can forgo more math classes.