Lesson objective: Add fractions with like denominators using a number line.

This lesson helps to build procedural skill in adding fractions with like denominators. Students work toward this goal in 3 ways:

- By using their understanding of decomposing fractions into unit and non-unit fractions.
- Through the use of joining lengths on a number line.
- Finding values that make equations true.

Students engage in Mathematical Practice 4 (modeling with mathematics) by modeling addition as lengths on a number line. This is especially important in the practice section of the lesson as students verify sums using the understanding that the size of the unit lengths does not change when adding fractions with like denominators. Mathematical Practice 2 (reason abstractly and quantitatively) is important as students reason about fractions with and without the support of a number line.

Special Materials:
Optional: Blank number lines