Teacher presentation materials. Unit: 6.2 Introducing Ratios (Grade 6). 6.2 Introducing Ratios In this unit, students learn to understand and use the terms “ratio,” “rate,” “equivalent ratios,” “per,” “at this rate,” “constant speed,” and “constant rate,” and to recognize when two ratios are or are not equivalent. They represent ratios as expressions, and represent equivalent ratios with double number line diagrams, tape diagrams, and tables. They use these terms and representations in reasoning about situations involving color mixtures, recipes, unit pricing, and constant speed. Read More Lessons Resources Assessments Lessons What are Ratios? 1 Introducing Ratios