# Lesson 21

Rompecabezas de fichas geométricas (optional)

## Warm-up: Observa y pregúntate: Abejas de fichas geométricas (10 minutes)

### Narrative

The purpose of this warm-up is to elicit student ideas about composing the same shape in different ways. While students may notice and wonder many things about these shapes, how the same shape is composed in different ways and the ways to describe the shapes are the important discussion points. Students are encouraged to carefully explain the shapes they see using the geometric language they’ve learned in previous lessons (MP6). For example, “The hexagon in one bee is made up of 2 rhombuses and 2 triangles in the other bee.”

### Launch

• Groups of 2
• Display the image.
• “¿Qué observan? ¿Qué se preguntan?” // “What do you notice? What do you wonder?”
• 1 minute: quiet think time

### Activity

• “Discutan con su pareja lo que pensaron” // “Discuss your thinking with your partner.”
• 1 minute: partner discussion
• Share and record responses.

### Student Facing

¿Qué observas? ¿Qué te preguntas?

### Activity Synthesis

• “La figura se parece a una abeja. ¿En qué se parecen estas dos abejas?” // “The shape looks like a bee. How are these two bees similar?” (They are the same shape and size. They have two trapezoids.)
• “¿En qué son diferentes?” // “How are they different?” (One bee has 2 hexagons, but no rhombuses or triangles. The other has 4 rhombuses and 4 triangles, but no hexagons. One has 4 pieces all together, the other has 10 pieces.)
• “En nuestra primera actividad de hoy, vamos a seguir pensando en cómo hacer la misma figura de diferentes maneras usando fichas geométricas” // “We are going to keep thinking about how to make the same shape in different ways using pattern blocks in our first activity today.”

## Activity 1: Rompecabezas de fichas geométricas (15 minutes)

### Narrative

In this activity, students create their own Pattern Block Puzzles for each other. During the activity they must adhere to mathematical constraints and are encouraged to use mathematical language to compare the different ways they can complete each puzzle. Monitor for the different ways students use the mathematical language they learned throughout the unit, including ways they identify the names of shapes they compose and the way they use words like halves, thirds, or fourths to describe ways they compose shapes out of same-size pieces (MP6).

Action and Expression: Provide Access for Physical Action. Provide access to pre-cut materials to reduce barriers for students who need support with fine-motor skills and students who benefit from extra processing time.
Supports accessibility for: Fine Motor Skills, Organization, Visual-Spatial Processing

### Required Materials

Materials to Gather

### Launch

• Groups of 4
• Give each student a piece of card stock and each group pattern blocks.
• “Vamos a usar hexágonos, trapecios, rombos azules y triángulos para hacer rompecabezas para nuestras parejas” // “We’re going to use hexagons, trapezoids, blue rhombuses, and triangles to make puzzles for our partners.”

### Activity

• “Tracen cada ficha geométrica en la hoja de puntos (en papel grueso). Cuando terminen, intercambien su hoja con alguien de su grupo para completar la actividad” // “Trace each pattern block on the blank puzzle paper (card stock). When you’re done, trade with someone in your group to complete the activity.“
• 5 minutes: independent work time
• 5 minutes: partner work time

### Student Facing

1. Haz un rompecabezas usando 4 fichas geométricas. Usa por lo menos un hexágono.
2. Traza cada ficha geométrica en la hoja de puntos.
3. Intercambia la hoja en la que trazaste el rompecabezas con otra persona de tu grupo.
4. Usa las fichas geométricas para mostrar dos maneras diferentes de hacer el rompecabezas de tu pareja. Dibuja las dos maneras.

Rompecabezas 1

Rompecabezas 2
5. Comparte algo que hayas observado acerca de los rompecabezas.

### Activity Synthesis

• Invite students to share what they noticed with members of their group and/or the class.

## Activity 2: La “Tienda de fichas geométricas” (15 minutes)

### Narrative

In this activity, students solve addition problems using money based on the Pattern Block Puzzles they sketched in the last activity.

The launch of the activity is an opportunity for students to reason which of the two designs will cost more before they complete any computations.

MLR7 Compare and Connect. Synthesis: After all strategies have been presented, lead a discussion comparing, contrasting, and connecting the different approaches. Ask, “¿Alguien resolvió el problema de la misma forma, pero lo explicaría de otra manera?” // “Did anyone solve the problem the same way, but would explain it differently?”, “¿Qué tenían en común las representaciones?” // “What did the representations have in common?”, “¿En qué eran diferentes?” // “How were they different?”

### Launch

• Groups of 2
• “En la ‘Tienda de fichas geométricas’, cada ficha geométrica tiene un precio diferente” // “At the Pattern Block Store, each pattern block shape has a different price.”
• Display the price list.
• “¿Cuál de los dos rompecabezas que dibujaron piensan que será más costoso de hacer: el rompecabezas 1 o el 2?” // “Which of the two puzzles that you sketched do you think will cost more to make? Puzzle 1 or 2?”
• 30 seconds: quiet think time
• 1 minute: partner discussion
• Share responses.

### Activity

• “Usa la lista de precios para descifrar cuánto costaría cada uno de tus dos rompecabezas” // “Use the price list to figure out how much your two puzzles would cost.”
• 5 minutes: independent work time
• 5 minutes: partner discussion
• As students work, look for different addition strategies. Monitor for students who:
• add bigger or smaller coins first

### Student Facing

figura costo

¿Cuánto costaría en la “Tienda de fichas geométricas” cada uno de los dos rompecabezas que dibujaste? Muestra o explica tu razonamiento.

1. Rompecabezas 1:
2. Rompecabezas 2: