# Lesson 3

Partial Products in Algorithms

### Lesson Purpose

### Lesson Narrative

In previous lessons, students multiplied three-digit numbers and two-digit numbers, using strategies based on place value and the properties of operations. Students used diagrams to illustrate and explain their partial products calculations.

In this lesson, students move from diagrams to an algorithm that records partial products which they used in an earlier course when multiplying a two-digit number and a two-digit number. Students relate partial product expressions to diagrams and then analyze a systematic way to record partial products. This work sets students up to learn the standard algorithm in the next lesson.

- Action and Expression

- MLR8

### Learning Goals

Teacher Facing

- Multiply a three-digit number and a two-digit number.
- Represent a partial products algorithm.

### Student Facing

- Let’s find partial products.

### Required Materials

Materials to Copy

- Partial Product Expressions

### Required Preparation

Activity 1:

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

### 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

### Suggested Centers

- Number Puzzles: Multiplication and Division (4–5), Stage 1: Two-digit Factors (Supporting)

### Print Formatted Materials

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Student Task Statements | docx | |

Lesson Cover Page | docx | |

Cool Down | Log In | |

Teacher Guide | Log In | |

Teacher Presentation Materials | docx | |

Blackline Masters | zip |