standard_description: Multiply matrices by scalars to produce new matrices, e.g., as when all of the payoffs in a game are doubled.
problem_activity: Narrative
This warm-up prompts students to carefully analyze and compare features of expressions and equations. When students compare the drawing, expression, and equations, they must use language precisely to describe how each is the same or different (MP6). Listen to the language students use to describe the different characteristics of each expression and equation and connect students' language to the new terms, factor and product, that are introduced in the synthesis.
Launch
Groups of 2
Display the image, expression, and equations.
“Pick one that doesn’t belong. Be ready to share why it doesn’t belong.”
1 minute: quiet think time
Activity
“Discuss your thinking with your partner.”
2-3 minutes: partner discussion
Share and record responses.
Student Facing
Which one doesn't belong?
A
[IMG]
B
\(3\times5\)
C
\(2\times5 =10\)
D
\(7 + 8 = 15\)
Student Response
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Activity Synthesis
“How is C different from the other ways we’ve represented equal groups before?” (It has an equal sign. It’s an equation.)
“C is a multiplication
equation
because it contains a multiplication symbol and the equal sign.”
“There are words that help us talk about different parts of the multiplication equation. The
factors
are the numbers being multiplied. The
product
is the result of multiplying some numbers. In the equation in C, the numbers 2 and 5 are the factors. The product is 10. Keep these words in mind today as we work with other multiplication equations.”


aligns: no