Using proportional reasoning

This lesson develops the concept of classifying relationships between two quantities. In particular, students will:

• Describe a ratio relationship between two quantities
• Compare ratios expressed in different ways
• Use proportional reasoning to solve a real-world problem

An introductory task looks at two examples of mixing orange with soda. Students must determine if there will be a difference in taste between the two mixes.

There is a collaborative activity that represents mixing orange with soda using picture cards. There are also instruction cards for mixing the two ingredients. The cards must be placed in order so that the resulting drinks go from the weakest to strongest taste of orange.

There are pre-lesson and post-lesson formative assessment tasks. Detailed teacher notes give suggestions on questioning and how to use the resources. Full solutions are given for each of the sections.

This is a concept development lesson from the Mathematics Assessment Resource Service, a collaboration between UC Berkeley and the Shell Centre team at the University of Nottingham. Further information on the collection is given here.