# Lesson 11 Make Sense of Decimal Addition

Let’s add decimals.

## Warm-up How Many Do You See: Grids

How many do you see? How do you see them?

## Activity 1 The Sum

Find the value of the expression. Show your thinking. Organize it so it can be followed by others.

What questions do you have about adding decimals?

## Activity 2 Target Numbers: Add Tenths or Hundredths

Directions:

Play one round of Target Numbers.

Partner A

Start at 0. Roll the number cube. Choose whether to add that number of tenths or hundredths to your starting number.

Write an equation to represent the sum.

Take turns until you’ve played 6 rounds.

Each round, the sum from the previous equations becomes the starting number in the new equation.

The partner to get a sum closest to 1 without going over wins.

Describe a move that you could have made differently to change the outcome of the game.

## Practice Problem

## Problem 1

Mai and Tyler were playing “Target Number Addition.”

Mai rolled 6 sixes. How close can Mai get to 1 without going over?

Tyler rolled 6 fours. How close can Tyler get to 1 without going over?