Lesson 18 Lots of Fractions to Add

Warm-up Number Talk: A Bunch of Numbers

Find the value of each expression mentally.

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	$\frac{12}{100}$	$3$	$1$
10 centavos	$\frac{22}{100}$	$0$	$1$
1 peso	$\frac{16}{100}$	$0$	$1$
2 pesos	$\frac{14}{100}$	$0$	$1$
5 pesos	$\frac{2}{10}$	$1$	$1$
20 pesos	$\frac{25}{100}$	$2$	$1$

If Diego and Lin each stack their centavo coins, whose stack would be taller? Show your reasoning.
If they each stack their peso coins, whose stack would be taller? Show your reasoning.
If they each stack all their coins, whose stack would be taller? Show your reasoning.
If they combine their coins to make a single stack, would it be more than 2 centimeters tall? Show your reasoning.

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

Diego and Lin continued to play with their coins.

Diego said that he has exactly 3 coins whose thickness adds up to $\frac{50}{100}$ cm. What coins does Diego have? Explain or show your reasoning.