Lesson 17

The purpose of this lesson is for students to use equivalent fractions to add tenths and hundredths, where the sum is greater than 1.

Prior to this lesson, students learned to combine tenths and hundredths up to a sum of 1. In this lesson, they extend that work to include larger fractions and continue to build their ability to identify equivalent fractions that are helpful for finding sums.

They also encounter some equations involving unknown addends. While subtracting tenths and hundredths is not an expectation at this point, students can reason about the unknown addends by relying on their understanding of addition, their experience with decomposing a fraction into a sum, and their knowledge of equivalence.

• Create a set of cards from the blackline master for each group of 2-4 students.

• Create a set of cards from the blackline master for each group of 2.

What questions that you asked supported students’ thinking about equivalence and addition of fractions today? What did students say or do that showed they were effective?