# Lesson 11 How Did You Do That?

Let’s add two-digit numbers and make sense of equations.

## Warm-up True or False: Add to a Two-digit Number

Decide if each statement is true or false. Be prepared to explain your reasoning.

## Activity 1 How Much Litter?

Mai and her classmates volunteer to clean up the local park.

They pick up 37 plastic bottles and 25 paper wrappers.

How many pieces of litter did they pick up all together?

Jada, Kiran, and Tyler find the value of

Jada’s way:

Kiran’s way:

Tyler’s way:

## Activity 2 It’s Your Turn to Add

Find the value of

.

Show your thinking using drawings, numbers, or words.If you have time… Think about a math story this expression could represent.

Share your stories with a partner.

## Practice Problem

## Problem 1

Use your favorite method to find the value of

Why do you like the method you chose?