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Lesson Plan
Subtraction strategies  Counting back within 20
First (1)  Math
LEARNING TARGET
 Students will be able to use the subtraction strategy of counting back on a number line to solve subtraction sentences with 20.
 Students will be able to identify the correct direction to count back on a number line.
 Students will be able to solve subtraction problems involving numbers up to 20.
LEARNING PROGRESSION
PREREQUISITE SKILL
null  null
EXTENSION SKILL

DURATION
4555 MInutes
MATERIALS
 Number line chart
 Whiteboard and markers
 Subtraction worksheet pack
 Manipulatives (optional)
VOCABULARY
 Subtract
 Minus
 Difference
 Count back
 Number line
TEACHING RESOURCES
CENTERS & TASK CARDS
No Centers or Task Cards Available
IEP GOAL WORKBOOKS
5 AND 1 INTERVENTIONS
No Interventions Available
GAMES
ACTIVITIES
No Activities Available
LESSON INSTRUCTION
INTRODUCTION
 Begin the lesson by reminding students of the concept of subtraction and its symbol, the minus sign ().
 Explain to students that they will be learning how to use a number line to help them subtract numbers up to 20.
 Display the number line chart and explain that they will be using this to help them count back to find the difference.
INSTRUCTION
 Demonstrate to the students how to use a number line to count back and solve subtraction problems. Start with a simple problem, such as 10  3.
 Show students how to start at the larger number, 10, and count back 3 spaces on the number line to get to the difference, which is 7. Write the subtraction sentence 10  3 = 7 on the board.
 Explain to students that they can use this method to subtract any two numbers up to 20.
 Provide additional examples and have students practice using the number line to count back and find the difference.
GUIDED PRACTICE
 Provide students with a subtraction worksheet containing problems that use numbers up to 20.
 Work through the problems together as a class, demonstrating how to use the number line to count back and find the difference.
 Encourage students to write the subtraction sentences for each problem on their worksheet.
INDEPENDENT PRACTICE
 Provide students with another subtraction worksheet to complete independently.
 Encourage students to use the number line to count back and find the difference.
 Circulate around the room to provide individual support and guidance as needed.
HOMEWORK
EXIT TICKET
 Provide each student with a whiteboard and marker.
 Instruct students to solve a subtraction problem using the number line to count back and find the difference.
ASSESSMENT
 Ask students to share one subtraction problem they solved using the number line to count back and find the difference.
 Use their responses to assess their understanding of the concepts and strategies covered in the lesson.
CLOSURE
 Recap with the class what they learned in the lesson about using the number line to count back and solve subtraction problems.
 Encourage students to reflect on how they can apply this strategy in future math lessons and in everyday situations.
 Provide positive reinforcement to the class for their hard work and progress throughout the lesson.
EXTENSION
 For students who have mastered subtracting numbers up to 20, provide them with more challenging subtraction problems that involve regrouping or borrowing.
 Students can create their own subtraction problems using the number line and exchange with a partner to solve.
INTERVENTION
 For students who struggle with fine motor skills or have difficulty writing on a small scale, provide them with larger print worksheets or whiteboards to work on.
 For students who need extra support, provide them with additional practice problems and oneonone guidance during independent practice.
 For students who need additional reinforcement, provide them with visual aids, such as posters or anchor charts, that illustrate the counting back strategy and the number line.
VIDEOS
No Video Available
TEACHING TIPS
 Provide plenty of opportunities for students to practice counting back on the number line before moving on to independent practice.
 Use manipulatives, such as counters or cubes, to help students visualize the counting back process.
 Encourage students to check their work by counting forward from the difference to the larger number to ensure they have the correct answer.
STUDENT MISCONCEPTIONS
 Students may struggle to identify the correct direction to count back on the number line.
 Students may get confused with the order of the numbers and accidentally subtract the smaller number from the larger number instead of vice versa.
 Some students may have difficulty remembering to write the subtraction sentence correctly, including the correct symbol and order of the numbers.
STANDARD
Common Core Standard:
1.OA.C.5  Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).
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