# Lesson 12

Solve Problems

### Lesson Purpose

The purpose of this lesson is for students to solve problems that involve adding and subtracting fractions with unlike denominators.

### Lesson Narrative

In this lesson, students apply their understanding of fraction addition and subtraction to solve multi-step problems. They work with fractions and mixed numbers and make estimates as well as finding the value of sums and differences. Students find the sums and differences in a way that makes sense to them. They will choose common denominators and can also use techniques they have seen in earlier lessons such as adding on to make a whole number.

- Representation

- MLR6

### Learning Goals

Teacher Facing

- Solve problems involving addition and subtraction of fractions with unlike denominators.

### Student Facing

- Let’s solve more problems by adding and subtracting fractions with unlike denominators.

### Required Preparation

### Lesson Timeline

Warm-up | 10 min |

Activity 1 | 20 min |

Activity 2 | 15 min |

Lesson Synthesis | 10 min |

Cool-down | 5 min |

### Teacher Reflection Questions

What strategies did most students use to add and subtract fractions today? What strategies did you anticipate? Which did you not anticipate?

### Suggested Centers

- How Close? (1–5), Stage 9: Add Fractions to 5 (Addressing)
- Creating Line Plots (2–5), Stage 3: Eighth Inches, Add and Subtract (Supporting)