Understanding the concept of "one more and one less" is foundational to developing strong numerical fluency in early math education. In this lesson, learners will explore how numbers progress and regress in the counting sequence. By using various concrete models and engaging in practice exercises, they will develop the skills needed to quickly solve problems involving adding or subtracting one.
Learning about "one more and one less" helps learners transition from counting to addition and subtraction by providing them with a foundational understanding of numerical progression and regression, enabling them to efficiently perform basic arithmetic operations.
The core concept revolves around understanding that as we move up or forwards through the counting sequence, the quantity increases by one, whereas moving down or backwards decreases the quantity by one.
Learners grasp this concept through various models like block towers, ten-frames, and number lines, providing visual and tactile representations of numerical progression.
Mastering "one more and one less" enables learners to swiftly solve problems involving adding or subtracting one, enhancing their computational efficiency and fluency in arithmetic operations.
Teaching Plan
The following activities will help your learner become confident with exploring "one more and one less." Remember to work at a pace that is comfortable for your learner.
Examples and visuals to support the lesson:
1. Exploring One More
This activity will introduce your learner to the concepts of "one more and one less." You will need block cubes, multilinks, or similar stackable items in two different colors.
Create a staircase arrangement with the blocks, ensuring that the block at the top of each column is a different color than the ones under it. Prompt your learner to observe the arrangement and ask if they notice any patterns emerging.
Next, isolate one column at a time to focus on. Encourage your learner to describe what they see in full sentences, making connections to previous concepts they learned about partitioning numbers one to five.
For example, if a column has 3 blue blocks with 1 red block at the top, your learner can describe it as "4 blocks split into 3 blue and 1 red." Reinforce this understanding by drawing a bar model to represent 4 partitioned into 3 and 1.
Don’t forget to explore the column with just one block. Using the red-blue example, that column would consist of just 1 red block.
Skill Check
I can use math tools to represent one more and show the number after.
2. Exploring One Less
Next, we'll explore the concept of "one less" using block towers and other representations such as counters on ten-frames.
Begin by asking your learner to describe consecutive number pairs in full sentences, focusing on the relationship between each pair.
As your learner becomes more comfortable with identifying consecutive number pairs, guide them towards the generalized statement: "the number before a given number is one less, and the number after a given number is one more." Encourage them to articulate this idea in their own words.
To reinforce this concept visually, reassemble the block staircase, highlighting the pattern of one less as you move down the staircase. This hands-on exploration helps solidify understanding and lays the groundwork for further practice with identifying one less in various contexts.
Skill Check
I can use math tools to represent one less and show the number before.
3. Movement as Magnitude
Explore the concept that movement in the counting sequence corresponds to a change in the number's magnitude. In other words, the number after is larger by one, while the number before is smaller by one.
Use previous representations such as block towers, ten-frames, and other visual aids to demonstrate this concept. Prompt your learner to observe the changes in quantity as they move through the counting sequence.
For example, as we move up or forwards through the counting sequence, the quantity increases by one, while moving down or backwards decreases the quantity by one.
You can also introduce a number line to further illustrate this concept. The number line provides a visual representation of the counting sequence, ensuring that zero is included. Encourage your learner to observe how moving forward along the number line increases the value by one, while moving backward decreases the value by one.
Skill Check
I understand that the number before is one less and the number after is one more.
4. Practice Exercises for One More and One Less
Provide your learner with a variety of practice exercises to develop fluency in understanding "one more and one less." Encourage them to use concrete objects or drawings to solve problems and justify their answers, fostering a deeper understanding of the concepts.
Examples of practice exercises include:
Completing "one more or one less" sentences presented in different ways, with a numeral missing that they fill in.
"Convince me" problems, where learners must justify statements such as "two is one less than three" or "four is one more than three."
Real-world problems where the answer cannot be seen, such as placing coins in a piggy bank so they can't be counted, then adding or removing coins and asking how many there are.
Connecting the concept to real-world problems involving measurement or time, such as calculating travel time on a train journey with multiple stops.
5. Challenge Tasks
To conclude the lesson, engage your learner with challenge questions designed to encourage critical thinking and assess their depth of understanding. Here are some challenge tasks for "one more and one less":
Using number cards with 0 to 5, explore different ways to fill in each statement. For example:
Statement 1: ___ is one less than ___.
Statement 2: ___ is one more than ___.
Jan picks a number card showing 3 and says "three is one less than two." Is she correct? Explain why.
"One more than three is the same as one less than five." Can you write another sentence like this?
Can I use the same number to fill both of these sentences? Why or why not?
One more than ___ is one.
One less than ___ is one.
Chloe is one year older than Seb. Seb is one year older than Adlar. Adlar is two years old. How old is Chloe? Who is the oldest? Use drawings or words to explain your thinking.
Skill Check
I can use what I know about one more and one less to solve problems.
Summary
In this lesson, your learner has explored the concepts of "one more and one less." Through concrete representations such as block towers, ten-frames, and number lines, learners have gained a deeper understanding of how numbers progress and regress in the counting sequence. By mastering these concepts, learners enhance their problem-solving skills and numerical fluency, setting a solid foundation for future mathematical learning.
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Skill Check