Lesson 4

Escribamos números de tres dígitos

Warm-up: Cuántos ves: Bloques (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
• “¿Cuántos ven? ¿Cómo lo saben?, ¿qué ven?” // “How many do you see? How do you see them?”
• Flash the image.
• 30 seconds: quiet think time

Activity

• Display the image.
• “Discutan con su compañero lo que pensaron” // “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

¿Cuántos ves? ¿Cómo lo sabes?, ¿qué ves?

Activity Synthesis

• “¿Qué observaron sobre el orden de los bloques y el valor que los bloques representan?” // “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.)
• “Hoy vamos a leer y escribir números de tres dígitos. Presten atención a cómo el orden, o la posición, de cada dígito muestra el valor” // “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: Acertijos sobre valor posicional (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: “Estoy de acuerdo porque . . .” // “I agree because . . .” or “Estoy en desacuerdo porque . . .” // “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
• “Tengo 4 centenas, 3 unidades y 2 decenas” // “I have 4 hundreds, 3 ones, and 2 tens.”
• “¿Cuál de estos muestra el valor total escrito como un número de tres dígitos? Expliquen cómo lo saben” // “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

• “Van a resolver acertijos numéricos usando bloques en base diez” // “You are going to solve number riddles using base-ten blocks.”
• As needed, demonstrate the task with a student.
• “Por turnos, lean las pistas mientras su compañero usa bloques para formar el número” // “Take turns reading the clues, while your partner uses blocks to make the number.”
• “Asegúrense de que están de acuerdo antes de agregar cada número a la tabla” // “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

Resuelve cada acertijo y escribe el número de tres dígitos. Usa la tabla como ayuda para organizar los dígitos.
acertijo centenas decenas unidades número de tres dígitos
1
2
3
4
5
6
1. Tengo 2 unidades, 7 decenas y 6 centenas.
2. Tengo 3 unidades, 5 decenas y 2 centenas.
3. Tengo 7 centenas, 5 unidades y 3 decenas.
4. Tengo 5 centenas, ninguna decena y 9 unidades.
5. Tengo 4 unidades, 6 decenas y 3 centenas.
6. Tengo 8 decenas, 1 centena y ninguna unidad.

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, “¿En qué se diferencian 81, 801 y 810?” // “What is the difference between 81, 801, and 810?”

Activity 2: Dígitos en desorden (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

• “En cada caso, encuentren el número que hace que la ecuación sea verdadera” // “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

En cada caso, encuentra el número que hace que la ecuación sea verdadera. Si te ayuda, usa bloques en base diez o diagramas.

1. 4 centenas $$+$$ 6 decenas $$+$$ 2 unidades $$=$$ __________
2. 7 unidades $$+$$ 2 centenas $$+$$ 6 decenas $$=$$ __________
3. 3 decenas $$+$$ 5 centenas $$=$$ __________
4. 325 $$=$$ __________ centenas $$+$$ __________ unidades $$+$$ __________ decenas
5. 70 $$+$$ 300 $$+$$ 2 $$=$$ __________
6. 836 $$=$$ 6 $$+$$ 800 $$+$$ __________
7. Clare y Elena encontraron el número que hace que la ecuación sea verdadera:

7 unidades $$+$$ 3 centenas $$=$$ __________.

Ellas escribieron respuestas diferentes.

• Clare escribió 7 unidades $$+$$ 3 centenas $$=$$ 37.

• Elena escribió 7 unidades $$+$$ 3 centenas $$=$$ 307.

¿Con quién estás de acuerdo? Explica.

Activity Synthesis

• Share and record responses for each equation.
• “¿Cómo saben que su ecuación es verdadera?” // “How do you know your equation is true?”
• “¿En qué se parecen ambos lados de la ecuación? ¿En qué son diferentes?” // “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

“Hoy aprendimos que cuando se representan números con bloques en base diez, diagramas o expresiones, puede que el orden de las centenas, las decenas y las unidades no importe. Estas representaciones usan el tamaño de los bloques, distintas formas, marcas, palabras y números para aclarar cuáles unidades y valores se muestran. Aprendimos que cuando se representan números con dígitos en un número de tres dígitos, el orden de los dígitos es muy importante. El orden, o la posición, de cada dígito muestra la cantidad de centenas, decenas y unidades” // “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 dice 5 decenas $$+$$ 4 unidades $$+$$ 7 centenas $$=$$ 547. ¿Qué le dirían a Han sobre lo que pensó?” // “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.)