1.3.E

Math1st Grade

The Standard

explain strategies used to solve addition and subtraction problems up to 20 using spoken words, objects, pictorial models, and number sentences

Texas Essential Knowledge and Skills for Mathematics

Teacher's field guide

What This Standard Means

What Students Need to Do

Students solve addition and subtraction problems within 20 and explain how they found each answer. They connect spoken explanations, objects, drawings, and number sentences.

What Mastery Looks Like

Students solve problems within 20 accurately. They use counters, drawings, or number sentences and clearly explain strategies such as counting on, making ten, or breaking apart numbers.

Common Misconceptions

Students may choose the wrong operation or make a drawing that does not match their number sentence. Some can find an answer but cannot name or explain their strategy.

How to Assess It

Give the exit ticket: “Solve 13 − 5. Draw your strategy, write a number sentence, and explain how your drawing shows the answer.”

Lesson moves

Ways to Teach It

  1. Have students solve 8 + 7 with counters, arrange them to make ten, then explain each move to a partner.

  2. Ask, “How could you solve 14 − 6?” Students draw one method and write two sentences explaining their thinking.

  3. Play Strategy Match with cards showing problems, drawings, number sentences, and strategy names that students group into matching sets.

  4. Set up a pretend snack shop where students add purchases or subtract sold items, then explain each answer with objects and equations.

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