Videos and solutions to help Grade 3 students learn how to solve two-step word problems involving all four operations and assess the reasonableness of answers.

Common Core Standards:3.OA.3, 3.OA.5, 3.OA.7, 3.OA.8, 3.OA.1, 3.OA.2, 3.OA.4, 3.OA.6

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Lesson Plans and Worksheets for Grade 3

Lesson Plans and Worksheets for all Grades

More Lessons for Grade 3

Common Core For Grade 3

New York State Common Core Math Module 1, Grade 3, Lesson 21

Lesson 21 Concept Development

Directions (similar to RDW process):

1. Read and analyze together to determine known and unknown information.

2. Discuss how to model.

3. Model and label diagrams.

4. Discuss and agree on the steps needed to solve.

5. Write equations and solve.

6. Assess the reasonableness of the solution (ask, “Does our answer make sense? How do we know?”).

7. Write a complete sentence to answer the question.

8. Prepare a mini-presentation to explain your work on directions 1–7. Prepare to answer clarifying questions from the group.

Lesson 21 Homework

1. Tina eats 8 crackers for a snack each day at school. On Friday she drops 3 and only eats 5. Write and solve an equation to show the total number of crackers Tina eats during the week.

3. Mr. Nguyen plants 24 trees around the neighborhood pond. He plants equal numbers of Maple, Pine, Spruce, and Birch trees. He waters the Spruce and Birch trees before it gets dark. How many trees does Mr. Nguyen still need to water? Draw and label a tape diagram.

2. Ballio has a reading goal. He checks 3 boxes of 9 books out from the library. After finishing them, he realizes that he beat his goal by 4 books! Label the tape diagrams to find Ballio's reading goal.

3. Mr. Nguyen plants 24 trees around the neighborhood pond. He plants equal numbers of Maple, Pine, Spruce, and Birch trees. He waters the Spruce and Birch trees before it gets dark. How many trees does Mr. Nguyen still need to water? Draw and label a tape diagram.

4. Anna buys 24 seeds and plants 3 in each pot. She has 5 pots. How many more pots does Anna need to plant all of her seeds?

Rotate to landscape screen format on a mobile phone or small tablet to use the **Mathway** widget, a free math problem solver that **answers your questions with step-by-step explanations**.

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.