options: Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.

Add up to four two-digit numbers using strategies based on place value and properties of operations.

Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.

Explain why addition and subtraction strategies work, using place value and the properties of operations. (Explanations may be supported by drawings or objects.)

Mentally add 10 or 100 to a given number 100–900, and mentally subtract 10 or 100 from a given number 100–900.
problem_activity: Narrative
The purpose of this activity is for students to find combinations of coins with a value of 100 cents and understand that a dollar is the same as 100 cents. They add within 100 by grouping like coins, using a ten, or using counting on strategies. They find coin combinations that add up to 100 cents or 1 dollar and write the leftover amount as cents. This work builds on students’ understanding of a hundred.
Engagement: Develop Effort and Persistence.
Chunk the tasks by question and check in with students to provide feedback and encouragement after each question. Look for the students to be using a strategy and ask them to verbalize their solution to ensure they are on the right track.
Supports accessibility for: Language; Organization
Required Preparation
Add a dollar bill to the money poster showing the front and back to display in the launch.
Launch
Groups of 2
Display the poster with the dollar added.
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“We just saw that there are many different ways to use coins to make 100 cents. One dollar is also the same as 100 cents.”
“If I have a dollar and I found a quarter, how much money would I have?” (125 cents or \$1 and 25¢)
30 seconds: quiet think time
Display a dollar and a quarter and write $1 and 25¢.
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“When you write dollar amounts you use the \$ symbol. Use the ¢ symbol for the amount that cannot be grouped to make a dollar.”
Activity
“Now, you are going to work with a partner to make dollars and cents.”
10 minutes: partner work time
Monitor for students who show Priya's money in different ways to share in the Lesson Synthesis.
Student Facing
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Andre emptied his pockets and found these coins.
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How much money does he have? Show your thinking.
Han emptied his pockets and found these coins.
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How much money does he have? Show your thinking.
Priya has $1 and 18¢ in her pocket.
If Priya only had coins in her pocket, what coins could she have?
Represent Priya’s coins:
If Priya had 1 dollar bill and some coins, what coins could she have?
Represent Priya's money:
Student Response
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Advancing Student Thinking
If students show the value of Andre and Han's coins only in cents, consider asking:
“How did you find the total value of the coins?”
“How many dollars does _______ have? How many leftover cents would he have?”
“How could you say how much money _______has using dollars and cents?”
Activity Synthesis
“I noticed that when you were creating a coin collection for Priya, there were different solutions.”
“How is it possible that everyone represented the same amount of money?” (Different coins can show the same amount, but you need a different number of coins.)
Invite students to share different combinations of coins they used to make $1.
Share and record responses.


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