# Lesson 7

Subtract Two Digits

### Lesson Purpose

### Lesson Narrative

In previous lessons, students learned that decomposing a ten is sometimes necessary when subtracting two numbers. Students used connecting cubes and base-ten blocks to represent their methods when subtracting a one-digit number from a two-digit number.

In the fist activity, students use methods that make sense to them to subtract and compare their methods with a partner. In the activity synthesis, students make connections across different methods and representations and consider which tools and representations work best for them. In the second activity, students use base-ten blocks to represent expressions and decompose a ten when subtracting by place.

Students should have access to connecting cubes and base-ten blocks throughout the lesson and the cool-down.

- Representation

### Learning Goals

Teacher Facing

- Subtract a two-digit number from a two-digit number in a way that makes sense to them.

### Student Facing

- Let’s subtract with two-digit numbers.

### Required Materials

### Required Preparation

Activity 2:

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

### Lesson Timeline

Warm-up | 10 min |

Activity 1 | 15 min |

Activity 2 | 20 min |

Lesson Synthesis | 10 min |

Cool-down | 5 min |

### Teacher Reflection Questions

### Suggested Centers

- Capture Squares (1–3), Stage 3: Add within 20 (Addressing)
- Five in a Row: Addition and Subtraction (1–2), Stage 6: Add within 100 with Composing (Addressing)
- Target Numbers (1–5), Stage 4: Subtract Tens or Ones (Addressing)

### Print Formatted Materials

Teachers with a valid work email address can click here to register or sign in for free access to Cool Down, Teacher Guide, and PowerPoint materials.

Student Task Statements | docx | |

Lesson Cover Page | docx | |

Cool Down | Log In | |

Teacher Guide | Log In | |

Teacher Presentation Materials | docx | |

Blackline Masters | zip |