# Lesson 9 Add 2 Two-digit Numbers

Let’s add two-digit numbers.

## Warm-up Number Talk: Make a Ten

Find the value of each expression mentally.

## Activity 1 How Did You Find the Value?

Find the value of

Show your thinking using drawings, numbers, or words.

## Activity 2 Grab and Add

## Problem 1

**Round 1:**Grab a handful of towers of ten and a handful of single cubes.

I have cubes and my partner has cubes.

How many cubes do you and your partner have altogether?

Show your thinking using drawings, numbers, or words.

## Problem 2

**Round 2:**

I have cubes and my partner has cubes.

How many cubes do you and your partner have altogether?

Show your thinking using drawings, numbers, or words.

## Problem 3

**Round 3:**

I have cubes and my partner has cubes.

How many cubes do you and your partner have altogether?

Show your thinking using drawings, numbers, or words.

## Problem 4

**Round 4:**

I have cubes and my partner has cubes.

Show your thinking using drawings, numbers, or words.

## Practice Problem

## Problem 1

Find the value of

Show your thinking using drawings, numbers, or words.