Lesson 3

The purpose of this lesson is to use understanding of equivalence to solve addition and subtraction problems with decimal fractions. Students also create their own word problems that involve the addition and subtraction of fractions.

In a previous lesson, students solved word problems that involved adding and subtracting fractions and using equivalent fractions. Here, students continue to apply their understanding of fractions to solve problems that require adding or subtracting decimal fractions. Students also show their understanding of the structure of fractions and word problems to create their own situations given a value or equation and some constraints. In doing so, they practice reasoning quantitatively and abstractly (MP2).

Invite students to use the Three Reads routine as needed to solve problems. If students need additional support with the concepts in this lesson, refer back to Unit 3, Section B in the curriculum materials.

Think about a time in today’s lesson when you asked questions to address a misconception or to clarify a student’s understanding. What questions were effective in surfacing a misunderstanding or the student’s thinking about the math? What questions would you ask differently and why?