standard_description: Use variables to represent two quantities in a real-world problem that change in relationship to one another; write an equation to express one quantity, thought of as the dependent variable, in terms of the other quantity, thought of as the independent variable. Analyze the relationship between the dependent and independent variables using graphs and tables, and relate these to the equation. For example, in a problem involving motion at constant speed, list and graph ordered pairs of distances and times, and write the equation d = 65t to represent the relationship between distance and time.
problem_activity: Narrative
The purpose of this Number Talk is for students to demonstrate strategies and understandings they have for multiplying multi-digit whole numbers. These understandings help students develop fluency. The products in the number talk get increasingly more cumbersome to keep track of mentally so students can identify times when products are more easily found mentally and when the algorithm, with pencil and paper, might be preferable.
Launch
Display one problem.
“Give me a signal when you have an answer and can explain how you got it.”
Activity
1 minute: quiet think time
Record answers and strategy.
Keep problems and work displayed.
Repeat with each problem.
Student Facing
Find the value of each expression mentally.
\(230 \times 10\)
\(230 \times 12\)
\(230 \times 15\)
\(232 \times 15\)
Student Response
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Activity Synthesis
“Which problem was the most challenging to solve mentally? Why do you think so?” (Answers vary, but students will likely mention one of the last three because there are different products to keep track of and add.)


aligns: no