standard_description: Interpret the equation y = mx + b as defining a linear function, whose graph is a straight line; give examples of functions that are not linear. For example, the function A = s2 giving the area of a square as a function of its side length is not linear because its graph contains the points (1,1), (2,4) and (3,9), which are not on a straight line.
problem_activity: Narrative
The purpose of this Number Talk is to elicit strategies and understandings students have for adding three one-digit numbers within 20. When students look for ways to decompose addends to make a ten with another addend, and add the remaining addends to find the sum, they look for and make use of the structure of numbers and properties of operations (MP7).
Launch
Display one expression.
“Give me a signal when you have an answer and can explain how you got it.”
1 minute: quiet think time
Activity
Record answers and strategies.
Keep expressions and work displayed.
Repeat with each expression.
Student Facing
Find the value of each expression mentally.
\(6 + 4 + 8\)
\(6 + 8 + 4\)
\(6 + 8 + 5\)
\(6 + 5 + 9\)
Student Response
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Activity Synthesis
“Who can restate _____'s reasoning in a different way?”
“Did anyone have the same strategy but would explain it differently?”
“Did anyone approach the problem in a different way?”


aligns: no