# Solving our Subtraction Problems

Lesson 3 of 5

## Objective: SWBAT apply their understanding of subtraction to create their own problems, as well as solve other's problems.

*45 minutes*

#### Review

*5 min*

*Yesterday you guys wrote some fantastic problems involving subtraction by using perimeter, shapes and shape attributes. I read so many of them last night and was so impressed, that I decided we needed to use them today in our work!*

Many of my students have struggled to remember shapes and shape attributes from last year so I have intentionally chosen to use shapes, attributes, and perimeter within this sequence of lessons. Students are doing the heavy lifting of creating the problems, instead of me just giving them problems, which teaches them what an important participant they are in our learning community. Students are having to apply what they know about shapes, math language and subtraction to create and solve these problems (MP4, MP6).

*Now who can help me with these examples on the board?*

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#### Activity

*35 min*

*I have mixed up all of your cards and have placed a stack of cards on each of your tables. Today, I want you to take 1 card at a time and show all of your work on a separate piece of paper. Remember, you may only turn it over to check your answer after you have solved it and shown all of your work.*

As students are working independently I am learning in to see how they are progressing. It's important to note any students who are struggling with the activity to quickly pull them into a small group to help them problem solve. I want to provide avenues for students to find solutions, but I don't want to give them the solutions. They need to find a way that makes sense for them and I help by guiding them to that place.

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#### Close

*5 min*

*What did you notice about your classmates work? What types of questions gave you trouble? What problem solving strategies did you use today?*

*Before you leave today I want you to show me how to apply your problem solving tools to these exit ticket questions. Be sure you show your work so I know how that brain is working!*

I do this check for understanding to see which students have mastered the concepts and which students will need additional intervention in the following days. An exit ticket allows me to see what work they show and where breakdowns might be occurring.

#### Resources

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- UNIT 1: Crazy About Fractions
- UNIT 2: Sharing Equally with Division
- UNIT 3: The Relationship Between Multiplication and Division
- UNIT 4: Number Lines
- UNIT 5: Multiply or Divide with Word Problems
- UNIT 6: Telling Time
- UNIT 7: Problem Solving
- UNIT 8: 2-Digit by 1-Digit Multiplication
- UNIT 9: Measurement and Data
- UNIT 10: Math in the Real World
- UNIT 11: More Problem Solving Practice
- UNIT 12: Addition & Subtraction
- UNIT 13: 3rd Grade Expectations
- UNIT 14: Geometry
- UNIT 15: Surveys and Graphing
- UNIT 16: Fun with Multiplying and Dividing