options: Counting & Cardinality: students learn to know number names and the count sequence, count to tell the number of objects, and compare numbers.

Operations & Algebra: students learn to solve problems using algebraic thinking and operations such as addition, subtraction, multiplication, and division. They may learn to identify and explain arithmetic patterns, evaluate or manipulate numerical expressions, and reason with equations and inequalities.

Measurement & Data: students learn to work with data and measure attributes such as time, money, length, area, and volume. They may learn to compare measurements to operations and convert between different units of measure.

Number & Operations in Base Ten: students learn to work with the base-ten system and build place value understanding.

Modeling: students learn to choose and use appropriate mathematics and statistics to analyze real-world empirical situations, improve decisions, and report on their conclusions and the reasoning behind them.

Number Systems and Quantity: students learn to understand the complex number system and reason quantitatively.

Functions: students learn to define, use, and evaluate functions to model relationships between quantities.

Geometry: students learn to classify geometric figures by their properties, and understand and compare the relationships between them. Students develop and use formulas to compute lengths, areas, and volumes, and they use transformations to generate new shapes and compare existing ones. Geometry can be studied with and without coordinates.

Number & Operations - Fractions: students learn to understand fractions as numbers and may work with them using addition, subtraction, multiplication, and division.

Statistics & Probability: students learn to analyze and produce data distributions, and build understanding of univariate and bivariate data. They learn to interpret data, make statistical inferences, justify conclusions, understand rules of probability, and use probability to make decisions.

Ratios & Proportional Relationships: students learn to recognize, describe, represent, and reason with ratios, rates, proportional relationships, and percent.
problem_activity: Narrative
The purpose of this activity is for students to visualize and make sense of the context of problems they will solve in the next activity. They will also consider representations that can be used to model the quantities and actions in the situation (MP4) and try creating them. Students will not have time to make a complete representation, so the focus is on making sense of the situation and persevering in finding effective representations (MP1).
Required Materials
Materials to Gather
Coins
Index cards
Paper
Two-color counters
Launch
Groups of 3 or 4
Display the image of the lockers.
“In your small group, discuss what you notice and wonder about the picture.”
1 minute: quiet think time
1 minute: group discussion
Share and record responses. If students are not familiar with lockers, explain that lockers are used to hold students’ coats, books, and backpacks in some schools.
Activity
Read the problem aloud to students.
“Take some time on your own to make sense of the problem. You may want to try to visualize it or reread the problem.”
2 minutes: quiet think time
Give students access to two-color counters, index cards, coins, and other materials that may be helpful to them.
“Based on what you know, create a representation of the problem.”
5 minutes: independent work time
Monitor for and select 3 different representations that:
represent lockers in different ways
show instances of contact with lockers (or of opening and closing)
show correspondence between each student and the lockers touched
Student Facing
The picture shows lockers in a school hallway.
The 20 students in Tyler’s fourth-grade class are playing a game in a hallway that is lined with 20 lockers in a row.
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The first student starts with the first locker and goes down the hallway and opens all the lockers.
The second student starts with the second locker and goes down the hallway and shuts every other locker.
The third student stops at every third locker and opens the locker if it is closed or closes the locker if it is open.
This process continues until all 20 students in the class have touched the lockers.
Create a representation to show what you understand about this problem. Consider:
How does your representation show lockers?
How does your representation keep track of students who touch lockers?
How does your representation show which lockers are open or closed?
Student Response
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Activity Synthesis
While discussing each representation, ask students:
“Where are the lockers in this representation?” (Numbers or pictures used to indicate lockers)
“How can we tell if a locker is open or closed in this representation?” (Symbols or colors used to indicate open or closed)
“How does this representation show which student is touching the lockers?” (Students and their actions listed in a table or a T-chart)
“In the next activity, you will answer questions about the game. You may use your representation or one shared by a classmate to help you think through the problems.”


correct_option_index: 1