# Lesson 9

Suma con una decena

### Lesson Purpose

The purpose of this lesson is for students to deepen their understanding that teen numbers are composed of a ten and some ones, and to find the value that makes an addition equation true when one addend is 10.

### Lesson Narrative

This lesson builds on the previous lesson in which students composed teen numbers using a ten and some ones. Students move from using connecting cube towers to filled-in 10-frames to represent teen numbers. Students also relate their composition work and the relationship between addition and subtraction to find values that make equations true.

Students continue using double 10-frames throughout the unit. Consider making copies on card stock so they can be used repeatedly.

- Representation

- MLR8

### Learning Goals

Teacher Facing

- Compose and decompose teen numbers into 1 ten and some number of ones.
- Find the value that makes an addition equation true, where one addend is 10.

### Student Facing

- Usemos una decena para formar números del 11 al 19.

### Required Materials

Materials to Gather

Materials to Copy

- Number Cards 11-20
- Double 10-Frame - Standard

### Required Preparation

Activity 1:

- Create a set of Number Cards (11-20) from the blackline master for each group of 2.

### CCSS Standards

Addressing

### 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 methods are students using when they build teen numbers: concrete objects on a 10-frame, drawings, numbers? How do these methods reflect their developing understanding of the unit ten?

### 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 |