Chapter 7: Ratio and Proportional Relationships

Standards for Mathematical Content in the CCSSM 

In the domain of Ratio and Proportional Relationships (Grades 6 and 7), students learn  ratio concepts, including the concept of unit rate associated with a ratio, and they use  ratio language, such as “3 cups flour to 2 cups water” and “3 cups flour for every 2 cups  water.” They reason about ratios and rates with the aid of tables, double number lines,  and strip diagrams to solve problems. They analyze and graph proportional relationships  and they distinguish them from other kinds of relationships. They also use proportional  relationships to solve multistep percent problems, such as problems involving percent  increase and decrease.  

Standards for Mathematical Practice in the CCSSM  

Opportunities to engage in all eight of the Standards for Mathematical Practice described  in the Common Core State Standards occur throughout the study of ratio and proportional  relationships, although the following standards may be especially appropriate for emphasis: 

• 2 Reason abstractly and quantitatively. Students engage in this practice when  they use a ratio to describe a quality that mixtures or other related quantities have  in common, and when they recognize that a single ratio can apply to both small and  large amounts of the mixture or the related quantities.  

• 4 Model with mathematics. Students engage in this practice when they use ratios and proportional relationships to model situations and when they examine relationships critically to determine if they are proportional or not and why or why not. 

• 5 Use appropriate tools strategically. Students engage in this practice when  they make and reason logically about ratio tables, double number lines, and strip  diagrams as they solve problems involving ratios and proportional relationships.