CK-12 Middle School Math - Grade 6, Volume 2 Of 2 CK-12's Middle School Math Grade 6 covers the fundamentals of fractions, decimals, and geometry. Also explored are units of measurement, graphing concepts, and strategies for utilizing the book’s content in practical situations. Volume 1 includes the last 6 chapters - Multiplication and Division of Fractions, Ratios, Proportions, and Percents, Geometric Figures, Geometry and Measurement, Integers, and Equations and Functions; Probability.