In this lesson plan, your learner will practice adding and subtracting 2 without relying on counting strategies by identifying patterns with odd and even numbers. Through targeted practice and engaging activities, your learner will progress from using visual aids to solving a variety of addition and subtraction problems.
The patterns that your learner will explore in this lesson will help them develop fluency in addition and subtraction. Here is a summary of the patterns for adding and subtracting 2:
Adding 2 to an odd number results in the next odd number (e.g., 3 + 2 = 5).
Adding 2 to an even number results in the next even number (e.g., 4 + 2 = 6).
Subtracting 2 from an odd number results in the previous odd number (e.g., 7 - 2 = 5).
Subtracting 2 from an even number results in the previous even number (e.g., 8 - 2 = 6).
Teaching Plan
The following activities will help your learner become confident in adding and subtracting 2. Be sure to work at a pace that is comfortable for your learner.
Examples and visuals to support the lesson:
1. Review Odd and Even Numbers
To add and subtract 2 without resorting to counting strategies, your learner will need to be able to confidently identify the next or previous odd or even number.
Begin by practicing counting odd and even numbers within 10 both forward and backward until your learner is fluent in this pattern.
Provide practice in the form of missing number problems where your learner must identify the previous odd number, next odd number, previous even number, and next even number.
Initially, they can use odd/even number lines for support but encourage them to progress to solving the problems without visual aids.
Skill Check
I can name the next odd or even number and the previous odd or even number.
2. Addition Story Problems
Provide a variety of addition story problems (part-part-whole and first-then-now) that involve adding two.
Have your learner write equations for the story problems and find the solutions. Draw attention to the fact that when two is added to an odd number the sum is the next odd number, and when two is added to an even number the sum is the next even number.
You can use a number line or tens frame to demonstrate the pattern visually. Emphasize that to calculate two more, we don't need to "count on" but instead can use our understanding of odd and even numbers.
Work towards using the generalized statements: "Adding two to an odd number results in the next odd number. Adding two to an even number results in the next even number."
Skill Check
I can use what I know about odd and even numbers to add 2 without counting.
3. Addition Equations
Once your learner understands the pattern, provide them with several addition equations where one of the addends is two.
Remind your learner of the commutative property of addition and how it can be used to solve problems where the first addend is two. For example, when solving 2 + 5, your learner can recognize that the expression can also be represented as 5 + 2 by reasoning that the solution is the next odd number after 5 (resulting in 7).
Encourage your learner to make connections with other addition strategies as well. For example, 8 + 2 can be found by finding the next even number after 8 or by recognizing that 8 and 2 are a pair that makes 10. They can also use their understanding of "one more" to reason that 1 + 2 is "one more than 2."
Skill Check
I can solve addition equations by adding 2 without counting.
4. Subtracting 2 from Odd and Even Numbers
After exploring addition of two, move on to subtracting two.
Provide a variety of subtraction story problems (part-part-whole and first-then-now) that involve subtracting two.
Have your learner write equations for the stories and solve them. Point out that the difference between consecutive odd or even number is always two.
Work towards the generalized statements: "Subtracting two from an odd number results in the previous odd number. Subtracting two from an even number results in the previous even number."
Just as with the addition problems, you can use number lines and tens frames to demonstrate the pattern.
Skill Check
I can use what I know about odd and even numbers to subtract 2.
5. Practice with Adding and Subtracting 2
Provide a variety of missing number problems that involve adding and subtracting 2. The problems can be in the form of equations, number lines, part-part-whole diagrams, and story problems. Here are some story problem examples:
Charlie has been on vacation for two days. He has five more days of vacation to go. How long is Charlie's vacation altogether?
Ellie has a seven-meter length of ribbon. She cuts off two meters to give to her friend. What length of ribbon does Ellie have now?
Skill Check
I can solve many types of problems that involve adding or subtracting 2.
Summary
In this lesson plan, your learner discovered that adding two to an odd number results in the next odd number, while adding two to an even number yields the next even number. Similarly, subtracting two from an odd or even number leads to the previous odd or even number, respectively. This understanding of number patterns will support your learner's ability to solve addition and subtraction problems efficiently and confidently, setting the stage for tackling more complex mathematical concepts with ease.
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Skill Check