This lesson builds on students' understanding of ratios by using a recipe to calculate unit ratios from fractional amounts. Students use ratios and proportional reasoning to correct a cooking error which relates to unit ratios. Students use strategies such as making a table or using multiplicative reasoning. This builds toward finding unit rates and ratios using fractional amounts as well as applying understanding of fraction multiplication and division.
Big Ideas:
Understand that the relationship between the quantities in a ratio is proportional and can be computed using a ratio table or multiplicative reasoning.
Understand how to compute a unit ratio using fractional amounts.
Vocabulary: ratio table, multiplicative reasoning, multiplicative inverse, reciprocal
Special Materials:
Measuring cups and spoons (optional)
Lesson plan