Georgia 3.MP.3
The Standard
Construct viable arguments and critique the reasoning of others.
Georgia's K-12 Mathematics Standards · Display perseverance and patience in problem-solving. Demonstrate skills and strategies needed to succeed in mathematics, including critical thinking, reasoning, and effective collaboration and expression. Seek help and apply feedback. Set and monitor goals.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students solve a problem and explain why their method works using equations, drawings, models, or words. They examine another person’s solution, identify what makes sense or not, and support their response with math evidence.
What Mastery Looks Like
- Students show a clear sequence of steps and support each step with a drawing, equation, model, or math fact. They can find an error in another solution, explain it politely, and suggest a correction.
Common Misconceptions
- Students may give only an answer and assume the work speaks for itself. They may reject any method different from their own, or criticize a classmate instead of identifying a specific step that does not make sense.
How to Assess It
- Give this exit ticket: “Mia says 47 + 28 = 615 because 4 + 2 = 6 and 7 + 8 = 15. Explain her error and solve correctly.”
Lesson moves
Ways to Teach It
Have partners build 36 + 27 with base-ten blocks, record each step, then swap models and check whether the explanation matches.
Ask, “Which method better shows why 6 × 4 equals 24, an array or equal groups?” Students write and defend their choice.
Use Error Detective cards with one incorrect solution per card, and award points for naming the exact error and correcting it.
Ask whether eight snack bags with six items each are enough for 45 students, then have partners compare and challenge their explanations.
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Printable 3.MP.3 Worksheet
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