3.1.G

Math3rd Grade

The Standard

display, explain, and justify mathematical ideas and arguments using precise mathematical language in written or oral communication

Texas Essential Knowledge and Skills for Mathematics

Teacher's field guide

What Students Need to Do: Students show a mathematical idea with words, numbers, symbols, diagrams, or objects. They explain their thinking and give a reason that supports their answer using accurate math terms.
What Mastery Looks Like: Students state an answer and support it with a clear equation, model, example, or definition. They use terms such as sum, difference, equal, tens, and ones correctly when speaking or writing.
Common Misconceptions: Students may give only an answer or list steps without explaining why the steps work. They may use vague words such as “it” or “bigger” instead of naming numbers, operations, or place values.
How to Assess It: Exit ticket: Solve 48 + 27, then explain why your answer is correct using an equation, a labeled model, and place-value words.

Lesson moves

Give pairs base-ten blocks to solve 36 + 28, then have each student explain how the blocks show regrouping.
Ask students to write: “I know 72 is greater than 68 because…” using place-value language and a comparison symbol.
Play Explanation Match by pairing equation cards with model cards and reasoning cards, then ask students to defend each match.
Have students compare two grocery totals and explain which costs more using equations, dollar amounts, and precise comparison words.

Keep exploring

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