Lesson 4
Write Threedigit Numbers
Warmup: How Many Do You See: Blocks (10 minutes)
Narrative
The purpose of this How Many Do You See is for students to use the structure of baseten blocks to determine the value of images (MP7). Students may name the quantity of the blocks they see by the unit each block represents (3 hundreds, 2 tens, and 4 ones), use an addition expression to name the value of each group of blocks (\(300 + 20 + 4\)), or name the number that represents the value of the blocks (324).
Launch
 Groups of 2
 “How many do you see? How do you see them?”
 Flash the image.
 30 seconds: quiet think time
Activity
 Display the image.
 “Discuss your thinking with your partner.”
 1 minute: partner discussion
 Record responses as an expression using hundreds, tens, and ones.
 Repeat for each image.
Student Facing
How many do you see and how do you see them?
Student Response
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Activity Synthesis
 “What did you notice about the order of the blocks and the value the blocks represent?” (Even though the blocks were in different orders, the first two images had the same value. The order of the blocks doesn’t change the value of the blocks.)
 “Today we are going to be reading and writing threedigit numbers. Pay attention to how the order, or place, of each digit shows the value.”
Activity 1: Place Value Riddles (20 minutes)
Narrative
The purpose of this activity is for students to use their understanding of place value to determine the number described in a riddle. Students then write the number of hundreds, tens, and ones, and represent the value as a threedigit number.
Advances: Conversing
Supports accessibility for: Attention, SocialEmotional Functioning
Required Materials
Materials to Gather
Launch
 Groups of 2
 Give students access to baseten blocks.
 “I have 4 hundreds, 3 ones, and 2 tens.”
 “Which of these shows the total value written as a threedigit number? Explain how you know.”
 Display 432, 234, 423.
 30 seconds: quiet think time
 1 minute: partner discussion
 Share responses.
Activity
 “You are going to solve number riddles using baseten blocks.”
 As needed, demonstrate the task with a student.
 “Take turns reading the clues, while your partner uses blocks to make the number.”
 “Make sure you agree before adding each number to the table.”
 10 minutes: partner work time
 If students finish early, ask them to write their own riddles and trade them with other groups to solve.
 Monitor for students who recognize they need a zero when writing the threedigit number in places where there were no tens or no ones.
Student Facing
riddle  hundreds  tens  ones  threedigit number 

1  
2  
3  
4  
5  
6 
 I have 2 ones, 7 tens, and 6 hundreds.
 I have 3 ones, 5 tens, and 2 hundreds.
 I have 7 hundreds, 5 ones, and 3 tens.
 I have 5 hundreds, no tens, and 9 ones.
 I have 4 ones, 6 tens, and 3 hundreds.
 I have 8 tens, 1 hundred, and no ones.
Student Response
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Activity Synthesis
 Invite previously selected students to share what they noticed when writing 509 and 180.
 As needed, write 81, 801, and 810 and ask, “What is the difference between 81, 801, and 810?”
Activity 2: Mixedup Digits (15 minutes)
Narrative
Required Materials
Materials to Gather
Launch
 Groups of 2
 Give students access to baseten blocks.
Activity
 “Find the number that makes each equation true.”
 6 minutes: partner work time
 Monitor for students who agree with Elena because:
 37 would mean 3 tens and 7 ones
 if there are 3 hundreds, you need 3 digits
Student Facing
Find the number that makes each equation true. Use baseten blocks or diagrams if they help.
 4 hundreds \(+\) 6 tens \(+\) 2 ones \(=\) __________
 7 ones \(+\) 2 hundreds \(+\) 6 tens \(=\) __________
 3 tens \(+\) 5 hundreds \(=\) __________
 325 \(=\) __________ hundreds \(+\) __________ ones \(+\) __________ tens
 70 \(+\) 300 \(+\) 2 \(=\) __________
 836 \(=\) 6 \(+\) 800 \(+\) __________

Clare and Elena worked to find the number that makes the equation true:
7 ones \(+\) 3 hundreds \(=\)__________.
They wrote different answers.

Clare wrote 7 ones \(+\) 3 hundreds \(=\) 37.

Elena wrote 7 ones \(+\) 3 hundreds \(=\) 307.
Who do you agree with? Explain.

Student Response
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Activity Synthesis
 Share and record responses for each equation.
 Consider asking:
 “How do you know your equation is true?”
 “How is each side of the equation the same? How is it different?”
 Invite previously identified students to share whether they agree with Clare or Elena and why.
Lesson Synthesis
Lesson Synthesis
“Today we learned that when you represent numbers with baseten blocks, diagrams, or expressions, the order of the hundreds, tens, and ones may not matter. These representations use the size of the blocks, different shapes, labels, words, and numbers to make it clear what units and values they show. We learned that when you represent numbers with digits in a threedigit number, the order of the digits is very important. The order, or place, of each digit shows others the amount of hundreds, tens, and ones.”
“Han says 5 tens \(+\) 4 ones \(+\) 7 hundreds \(=\) 547. What would you say to Han about his thinking?” (The number should be 754 because the 7 belongs in the hundreds place. You have to make sure each digit in the threedigit number matches the value, you can’t just put them in the same order.)
Cooldown: Order of Digits (5 minutes)
CoolDown
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