options: Interpret the structure of expressions.

Represent and analyze quantitative relationships between dependent and independent variables.

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

Add and subtract within 20.

Use polynomial identities to solve problems.

Reason about and solve one-variable equations and inequalities.

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

Apply and extend previous understandings of arithmetic to algebraic expressions.

Rewrite rational expressions.

Work with addition and subtraction equations.

Write expressions in equivalent forms to solve problems.

Use the four operations with whole numbers to solve problems.

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

Multiply and divide within 100.

Analyze patterns and relationships.

Solve systems of equations.

Represent and solve problems involving multiplication and division.

Write and interpret numerical expressions.

Solve equations and inequalities in one variable.

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

Represent and solve problems involving addition and subtraction.

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

Understand the relationship between zeros and factors of polynomials.

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

Use properties of operations to generate equivalent expressions.

Gain familiarity with factors and multiples.

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

Generate and analyze patterns.

Work with radicals and integer exponents.

Represent and solve equations and inequalities graphically.

Perform arithmetic operations on polynomials.

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

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

Create equations that describe numbers or relationships
problem_activity: Narrative
The purpose of this activity is for students to write equations for multiplication situations and diagrams using a symbol for the unknown number. When students write an equation to represent a situation, including a symbol for the unknown number, they model a situation with mathematics (MP4).
Students find an unknown factor or unknown product in multiplication problems. In this task, the unknown factor diagrams and situations only include the “how many groups” problem type and the factors 2, 5, and 10. This sets students up to skip-count to find the unknown number.
This problem type will be revisited extensively in future lessons and will be related to division. It is not necessary to make the connection to division now. In the synthesis students explain how the equations they wrote represent the diagram or situation.
Representation: Internalize Comprehension.
Synthesis: Invite students to identify which details were important or most useful to pay attention to. Display the sentence frame, “The next time I write an equation with an unknown number, I will . . . .“
Supports accessibility for: Visual-Spatial Processing
Launch
Groups of 2
Activity
“Now you will practice writing your own equations with a symbol for the unknown.”
2–3 minutes: independent work time
“Share your equations with your partner. Discuss how you know each equation matches the diagram or situation.”
2–3 minutes: partner discussion
Have a whole-class discussion focused on how the equations match the different representations.
Consider asking:
“How did you use the representations to write an equation with a symbol for the unknown?” (I looked for what was missing in the diagram. I thought about the situation to figure out if it was the number in each group, the number of groups, or the total that was missing.)
“Now find the missing number in each equation and write a new equation that includes the solution.”
3–5 minutes: partner work time
Student Facing
Write an equation to represent each diagram or situation. Use a symbol for the unknown. Be prepared to share your reasoning.
Find the number that makes each equation true. Rewrite the equation with the solution.
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 diagram or situation                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | equation with symbol | equation with solution |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------|------------------------|
| |https://cms-im.s3.amazonaws.com/gf3w2hjep7il38vg6usxrnj0zj9v?response-content-disposition=attachment%3B%20filename%3D%22tikz-file-152934.svg%22%3B%20filename%2A%3DUTF-8%27%27tikz-file-152934.svg&response-content-type=image%2Fsvg%2Bxml&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAXQCCIHWF3XOEFOW4%2F20240208%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240208T163829Z&X-Amz-Expires=604800&X-Amz-SignedHeaders=host&X-Amz-Signature=e5ec58d09b006a5b2fe4be0a8c6e1be79921b2ef4899756a6a2fb56b666e8275|  |https://cms-im.s3.amazonaws.com/gf3w2hjep7il38vg6usxrnj0zj9v?response-content-disposition=attachment%3B%20filename%3D%22tikz-file-152934.svg%22%3B%20filename%2A%3DUTF-8%27%27tikz-file-152934.svg&response-content-type=image%2Fsvg%2Bxml&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAXQCCIHWF3XOEFOW4%2F20240208%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240208T163829Z&X-Amz-Expires=604800&X-Amz-SignedHeaders=host&X-Amz-Signature=e5ec58d09b006a5b2fe4be0a8c6e1be79921b2ef4899756a6a2fb56b666e8275| image:: https://cms-im.s3.amazonaws.com/gf3w2hjep7il38vg6usxrnj0zj9v?response-content-disposition=attachment%3B%20filename%3D%22tikz-file-152934.svg%22%3B%20filename%2A%3DUTF-8%27%27tikz-file-152934.svg&response-content-type=image%2Fsvg%2Bxml&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAXQCCIHWF3XOEFOW4%2F20240208%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240208T163829Z&X-Amz-Expires=604800&X-Amz-SignedHeaders=host&X-Amz-Signature=e5ec58d09b006a5b2fe4be0a8c6e1be79921b2ef4899756a6a2fb56b666e8275 |                      |                        |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               Jada has some packs of sports cards. Each pack has 5 cards. If Jada has 45 cards, how many packs of cards does she have?                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                      |                        |
| |https://cms-im.s3.amazonaws.com/clhjdxlivcrwuhnz8p74h3wdr0sr?response-content-disposition=attachment%3B%20filename%3D%22tikz-file-148281.svg%22%3B%20filename%2A%3DUTF-8%27%27tikz-file-148281.svg&response-content-type=image%2Fsvg%2Bxml&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAXQCCIHWF3XOEFOW4%2F20240208%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240208T163829Z&X-Amz-Expires=604800&X-Amz-SignedHeaders=host&X-Amz-Signature=d838c3f51f69439465afa72015e1148ef93bd40389ba4d8f653044f160e7cc19|  |https://cms-im.s3.amazonaws.com/clhjdxlivcrwuhnz8p74h3wdr0sr?response-content-disposition=attachment%3B%20filename%3D%22tikz-file-148281.svg%22%3B%20filename%2A%3DUTF-8%27%27tikz-file-148281.svg&response-content-type=image%2Fsvg%2Bxml&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAXQCCIHWF3XOEFOW4%2F20240208%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240208T163829Z&X-Amz-Expires=604800&X-Amz-SignedHeaders=host&X-Amz-Signature=d838c3f51f69439465afa72015e1148ef93bd40389ba4d8f653044f160e7cc19| image:: https://cms-im.s3.amazonaws.com/clhjdxlivcrwuhnz8p74h3wdr0sr?response-content-disposition=attachment%3B%20filename%3D%22tikz-file-148281.svg%22%3B%20filename%2A%3DUTF-8%27%27tikz-file-148281.svg&response-content-type=image%2Fsvg%2Bxml&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAXQCCIHWF3XOEFOW4%2F20240208%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240208T163829Z&X-Amz-Expires=604800&X-Amz-SignedHeaders=host&X-Amz-Signature=d838c3f51f69439465afa72015e1148ef93bd40389ba4d8f653044f160e7cc19 |                      |                        |
| |https://cms-im.s3.amazonaws.com/jg4dxs24ozz1huvon7s4enxj1zdl?response-content-disposition=attachment%3B%20filename%3D%22tikz-file-148282.svg%22%3B%20filename%2A%3DUTF-8%27%27tikz-file-148282.svg&response-content-type=image%2Fsvg%2Bxml&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAXQCCIHWF3XOEFOW4%2F20240208%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240208T163829Z&X-Amz-Expires=604800&X-Amz-SignedHeaders=host&X-Amz-Signature=8cf7dafc0a1b5a31eead8875981bb2db673480a12c4a842012b6e72effafc408|  |https://cms-im.s3.amazonaws.com/jg4dxs24ozz1huvon7s4enxj1zdl?response-content-disposition=attachment%3B%20filename%3D%22tikz-file-148282.svg%22%3B%20filename%2A%3DUTF-8%27%27tikz-file-148282.svg&response-content-type=image%2Fsvg%2Bxml&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAXQCCIHWF3XOEFOW4%2F20240208%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240208T163829Z&X-Amz-Expires=604800&X-Amz-SignedHeaders=host&X-Amz-Signature=8cf7dafc0a1b5a31eead8875981bb2db673480a12c4a842012b6e72effafc408| image:: https://cms-im.s3.amazonaws.com/jg4dxs24ozz1huvon7s4enxj1zdl?response-content-disposition=attachment%3B%20filename%3D%22tikz-file-148282.svg%22%3B%20filename%2A%3DUTF-8%27%27tikz-file-148282.svg&response-content-type=image%2Fsvg%2Bxml&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAXQCCIHWF3XOEFOW4%2F20240208%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240208T163829Z&X-Amz-Expires=604800&X-Amz-SignedHeaders=host&X-Amz-Signature=8cf7dafc0a1b5a31eead8875981bb2db673480a12c4a842012b6e72effafc408 |                      |                        |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         The school has 6 bags. Each bag has 10 basketballs in it. How many basketballs does the school have?                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |                      |                        |
Student Response
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Advancing Student Thinking
If students write an equation without a symbol for the unknown number, consider asking:
“How does your equation represent the diagram (or situation)?”
“How could you show the number that was unknown with a symbol?”
Activity Synthesis
“What strategies did you use to find the unknown numbers?” (I counted by 2 to get the total. I counted by different numbers until I found a number that gave me the product.)
“How did each equation change as you found the unknown number?” (The symbol was replaced with the number.)


correct_option_index: 16