options: Understand the connections between proportional relationships, lines, and linear equations.

Work with equal groups of objects to gain foundations for multiplication.

Write expressions in equivalent forms to solve problems.

Analyze and solve linear equations and pairs of simultaneous linear equations.

Multiply and divide within 100.

Solve systems of equations.

Create equations that describe numbers or relationships

Perform arithmetic operations on polynomials.

Generate and analyze patterns.

Understand and apply properties of operations and the relationship between addition and subtraction.

Solve equations and inequalities in one variable.

Understand properties of multiplication and the relationship between multiplication and division.

Solve real-life and mathematical problems using numerical and algebraic expressions and equations.

Understand addition as putting together and adding to, and understand subtraction as taking apart and taking from.

Add and subtract within 20.

Interpret the structure of expressions.

Apply and extend previous understandings of arithmetic to algebraic expressions.

Use the four operations with whole numbers to solve problems.

Represent and solve problems involving addition and subtraction.

Represent and solve problems involving multiplication and division.

Analyze patterns and relationships.

Understand solving equations as a process of reasoning and explain the reasoning.

Use polynomial identities to solve problems.

Gain familiarity with factors and multiples.

Reason about and solve one-variable equations and inequalities.

Represent and analyze quantitative relationships between dependent and independent variables.

Use properties of operations to generate equivalent expressions.

Represent and solve equations and inequalities graphically.

Write and interpret numerical expressions.

Solve problems involving the four operations, and identify and explain patterns in arithmetic.

Rewrite rational expressions.

Work with addition and subtraction equations.

Understand the relationship between zeros and factors of polynomials.

Work with radicals and integer exponents.
problem_activity: Narrative
The purpose of this activity is for students to revisit stage 2 of the What's Behind My Back center, which was first introduced in grade 1. Students begin with a tower of 10 connecting cubes. They break apart the tower and represent the two parts with a drawing and an expression. Throughout the activity, students practice using what they know about sums of 10 and the relationship between addition and subtraction to find unknown addends. Students explain their reasoning about how they know how many cubes are missing to their partner (MP3). As students discuss, listen for the ways students show how they are looking for and using the counting sequence, properties of operations, or the relationship between addition and subtraction (MP7).
MLR8 Discussion Supports.
Make connections between representations visible. Think aloud, use gestures and a labeled display to show connections between parts of the equation and the cubes that are visible and those that are hidden.
Advances: Listening, Representing
Required Materials
Materials to Gather
Connecting cubes
Materials to Copy
What's Behind My Back Stage 2 Recording Sheet Grade 1
Required Preparation
Gather a tower of 10 connecting cubes to use in the launch.
Launch
Groups of 2
Give each group 10 connecting cubes.
“We are going to play a game you may have played in first grade called What’s Behind My Back?”
Show students a tower of 10 cubes. Put the tower behind your back. Break off 4 cubes, and display the rest of the tower.
“How many cubes are behind my back? How do you know?” (4 because there are 6 and 4 more makes 10. I know because
\(10 - 4 = 6\)
.)
30 seconds: quiet think time
1 minute: partner discussion
Share responses.
“After one partner has hidden the cubes, switch roles.”
Activity
10 minutes: partner work time
Activity Synthesis
Ask a student to play a round of the game with the class.
As the student displays the tower, write the related addition equation with an unknown addend on the board. (for example, if a student shows 2 blocks, write
\(2+\underline{\hspace{.5 cm}}=10\)
.)
“How does this equation represent the game?”
“What number makes the equation true?”
“How can we represent the game with a subtraction equation?” (
\(10 - 2 = 8\)
or
\(10 - 8 = 2\)
)
If needed, ask students to show how the numbers in the addition and subtraction equations represent the cubes in the round.


correct_option_index: 14