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# Lesson Plan

## Subtraction - one digit - Find Missing Numbers up to 18

### Second (2) - Math

### LEARNING TARGET

- Students will be able to solve subtraction problems with missing subtrahends up to 18.
- Students will be able to use the inverse operation of addition to check their answers.
- Students will be able to explain their problem-solving strategies.

### LEARNING PROGRESSION

###### PREREQUISITE SKILL

Learners can show ways to subtract 1 digit from a 2-digit number.

###### EXTENSION SKILL

null - null

###### DURATION

8 min Guided Practice, 20 min Independent Practice, 7 min Exit Ticket

###### MATERIALS

- Whiteboard and markers
- Index cards with subtraction problems (e.g. 10 - __ = 6)
- Manipulatives (e.g. counting cubes, ten frames, number lines)
- Worksheets with subtraction problems and missing subtrahends

###### VOCABULARY

- Subtraction
- Minuend
- Subtrahend
- Difference
- Inverse operation

### TEACHING RESOURCES

###### CENTERS & TASK CARDS

No Centers or Task Cards Available

###### IEP GOAL WORKBOOKS

What is a Math IEP Objective Workbook?

- 40 daily fluency assignments
- 8 student self-monitoring progress sheets with weekly goal setting
- 2 baseline assessments
- 8 formative assessments
- 1 present level of performance self-graphing data tracking sheet (Perfect for

progress reporting and IEP meeting) - Teacher answer keys

###### WORKSHEET PACK

No Worksheet Packs Available

###### 5 AND 1 INTERVENTIONS

No Interventions Available

###### GAMES

Games can be used as a reward, as an introduction to a concept, or for independent practice.

###### ACTIVITIES

No Activities Available

### LESSON INSTRUCTION

###### INTRODUCTION

- Review with students what subtraction means and how to subtract using manipulatives.
- Explain to students that sometimes we don't know one of the numbers we need to subtract, and that's called a missing subtrahend.
- Show an example of a subtraction problem with a missing subtrahend, such as "10 - __ = 6."
- Ask students how they would figure out what number is missing. Encourage them to discuss with a partner or in small groups.

###### INSTRUCTION

- Model how to solve a subtraction problem with a missing subtrahend using manipulatives and the inverse operation of addition.
- Show an example of a problem with manipulatives, such as using 10 cubes and taking away 6 to find the missing subtrahend of 4.
- Write the problem on the whiteboard and show how to use the inverse operation of addition to check the answer: 4 + 6 = 10.
- Provide additional examples as needed, using different manipulatives and problem types.

###### GUIDED PRACTICE

- Distribute a worksheet with subtraction problems with missing subtrahends to each student.
- Have students work in pairs to solve the problems using manipulatives and the inverse operation of addition to check their answers.
- Circulate around the room to provide support and guidance as needed.

###### INDEPENDENT PRACTICE

- Provide students with a worksheet containing subtraction problems with missing subtrahends.
- Instruct students to solve the problems independently using manipulatives and the inverse operation of addition to check their answers.
- Circulate around the room to provide support and guidance as needed.

###### HOMEWORK

- Provide students with a worksheet of subtraction problems with missing subtrahends to complete for homework.
- Encourage students to use manipulatives and the inverse operation of addition to check their answers.
- Remind students to bring their homework back to class to share with their classmates, but do not grade the homework.

###### EXIT TICKET

- Provide each student with an exit card with a subtraction problem with a missing subtrahend.
- Instruct students to solve the problem and write down their answer and problem-solving strategy.

###### ASSESSMENT

- Ask students to share their answers and problem-solving strategies for one of the problems from the independent practice worksheet.
- Use their responses to assess their understanding of solving subtraction problems with missing subtrahends.

###### CLOSURE

- Review with students what they learned about solving subtraction problems with missing subtrahends and how to use the inverse operation of addition to check their answers.
- Encourage students to continue practicing solving subtraction problems with missing subtrahends using manipulatives and the inverse operation of addition.

###### EXTENSION

- For students who have mastered solving subtraction problems with missing subtrahends, provide more challenging problems with larger numbers or multiple missing subtrahends.
- Encourage students to explain their problem-solving strategies and to work collaboratively to solve problems.
- Introduce related concepts such as regrouping or multi-step word problems.

###### INTERVENTION

- Provide additional manipulatives and visual aids to support students who need more hands-on practice.
- Break down the steps of problem-solving and provide additional practice problems with scaffolding.
- Offer small group or one-on-one instruction to provide individualized support and to address specific areas of difficulty.

###### VIDEOS

No Video Available

### TEACHING TIPS

- Use a variety of manipulatives to help students visualize and solve the problems.
- Encourage students to explain their problem-solving strategies to develop their mathematical reasoning skills.
- Provide opportunities for collaboration and discussion to foster a deeper understanding of the concepts.

### STUDENT MISCONCEPTIONS

- Students may struggle with understanding the concept of missing subtrahends.
- Some students may find it challenging to use the inverse operation of addition to check their answers.
- Students may make errors in subtraction due to difficulties with regrouping or borrowing.

### STANDARD

##### Common Core Standard:

2.OA.B.2 - Fluently add and subtract within 20 using mental strategies.

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