# Lesson 18 Lots of Fractions to Add

• Let’s add tenths and hundredths again, more than two at a time.

## Warm-up Number Talk: A Bunch of Numbers

Find the value of each expression mentally.

## Activity 1 Stack Centavos and Pesos

Diego and Lin each have a small collection of Mexican coins.

The table shows the thickness of different coins in centimeters (cm) and how many of each Diego and Lin have.

coin value

thickness in cm

Diego

Lin

1 centavo

10 centavos

1 peso

2 pesos

5 pesos

20 pesos

1. If Diego and Lin each stack their centavo coins, whose stack would be taller? Show your reasoning.

2. If they each stack their peso coins, whose stack would be taller? Show your reasoning.

3. If they each stack all their coins, whose stack would be taller? Show your reasoning.

4. If they combine their coins to make a single stack, would it be more than 2 centimeters tall? Show your reasoning.

## Activity 2 More Than Two Fractions

Find the value of at least 3 of the expressions. Show your reasoning.

## Problem 1

Diego and Lin continued to play with their coins.

Diego said that he has exactly 3 coins whose thickness adds up to cm. What coins does Diego have? Explain or show your reasoning.

coin

thickness in cm

1 centavo

10 centavos

1 peso

2 pesos

5 pesos

20 pesos