# Lesson 4

Write Three-digit Numbers

## Warm-up: 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 base-ten 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.
• 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?

### 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 three-digit 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 three-digit number.

MLR8 Discussion Supports. Display sentence frames to support partner discussion about each number written on the table: “I agree because . . .” or “I disagree because . . . .”
Engagement: Provide Access by Recruiting Interest. Provide choice. Invite students to decide the order in which they complete the work. They can start with any of the riddles, as long as they complete all of them.
Supports accessibility for: Attention, Social-Emotional Functioning

### Required Materials

Materials to Gather

### Launch

• Groups of 2
• “I have 4 hundreds, 3 ones, and 2 tens.”
• “Which of these shows the total value written as a three-digit 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 base-ten 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 three-digit number in places where there were no tens or no ones.

### Student Facing

Solve each riddle and write the three-digit number. Use the table to help you organize the digits.
riddle hundreds tens ones three-digit number
1
2
3
4
5
6
1. I have 2 ones, 7 tens, and 6 hundreds.
2. I have 3 ones, 5 tens, and 2 hundreds.
3. I have 7 hundreds, 5 ones, and 3 tens.
4. I have 5 hundreds, no tens, and 9 ones.
5. I have 4 ones, 6 tens, and 3 hundreds.
6. I have 8 tens, 1 hundred, and no ones.

### 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: Mixed-up Digits (15 minutes)

### Narrative

The purpose of this activity is for students to find the numbers that make equations true using what they know about the meaning of the digits in three-digit numbers. In each equation, the value of the digits are presented out of place value order. Throughout the activity, encourage students to explain how they know they have made true equations using precise language about the meaning of each digit in a 3-digit number (MP3, MP6).

### Required Materials

Materials to Gather

• Groups of 2

### 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 base-ten blocks or diagrams if they help.

1. 4 hundreds $$+$$ 6 tens $$+$$ 2 ones $$=$$ __________
2. 7 ones $$+$$ 2 hundreds $$+$$ 6 tens $$=$$ __________
3. 3 tens $$+$$ 5 hundreds $$=$$ __________
4. 325 $$=$$ __________ hundreds $$+$$ __________ ones $$+$$ __________ tens
5. 70 $$+$$ 300 $$+$$ 2 $$=$$ __________
6. 836 $$=$$ 6 $$+$$ 800 $$+$$ __________
7. Clare and Elena worked to find the number that makes the equation true:

7 ones $$+$$ 3 hundreds $$=$$__________.

• Clare wrote 7 ones $$+$$ 3 hundreds $$=$$ 37.

• Elena wrote 7 ones $$+$$ 3 hundreds $$=$$ 307.

Who do you agree with? Explain.

### Activity Synthesis

• Share and record responses for each equation.
• “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 base-ten 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 three-digit 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 three-digit number matches the value, you can’t just put them in the same order.)