# Lesson 10

Tens and Tens, Ones and Ones

### Lesson Purpose

The purpose of this lesson is for students to add 2 two-digit numbers using methods based on place value.

### Lesson Narrative

In the previous lesson, students added 2 two-digit numbers with composing a ten, in a way that made sense to them. This lesson focuses on adding tens and tens and ones and ones. This method is important because it sets students up to add multi-digit numbers in later grades. Students apply what they learned about the commutative and associative properties to see that it doesn’t matter if they add tens and tens first or ones and ones first.

• Representation
• MLR2

### Learning Goals

Teacher Facing

• Add two-digit numbers by adding tens and tens and ones and ones.

### Required Materials

Materials to Gather

Materials to Copy

• Number Puzzles Addition Stage 4 Gameboard

### Required Preparation

Activity 2:

• Create two separate posters that show base-ten drawings of 34 and 57. Leave space to write equations underneath the drawings.

Activity 3:

• Each group of 2 needs a set of digit cards from the previous center, Number Puzzles.

Building Towards

### Lesson Timeline

 Warm-up 10 min Activity 1 10 min Activity 2 15 min Activity 3 15 min Lesson Synthesis 10 min Cool-down 0 min

### Teacher Reflection Questions

In what ways does the work of this lesson lay the foundation for student understanding of the standard algorithm for addition, which will be used in later grades?

### Print Formatted Materials

For access, consult one of our IM Certified Partners.