Chapter 7: One More and One Less
Learn Grade 1 mathematics from very beginner explanations through worked examples, practice, reasoning, and review.
Chapter Overview
This chapter teaches One More and One Less with simple language, step-by-step reasoning, and original worked examples. Math words are explained in simple Grade 1 language.
Key Technical Terms
- One more with objects (a Grade 1 idea used in this chapter)
- One less with objects (a Grade 1 idea used in this chapter)
- One more on a number line (a Grade 1 idea used in this chapter)
- One less on a number line (a Grade 1 idea used in this chapter)
- One more within 20 (a Grade 1 idea used in this chapter)
- One less within 20 (a Grade 1 idea used in this chapter)
- One more within 50 (a Grade 1 idea used in this chapter)
- One less within 50 (a Grade 1 idea used in this chapter)
- Story problems with one more or less (a Grade 1 idea used in this chapter)
- One more and one less review (a Grade 1 idea used in this chapter)
How to Learn This Chapter
Read or listen to the explanation, use objects or pictures when helpful, follow one step at a time, and try the example again before checking the answer.
7.1 One more with objects
One more with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Beginner Note
Start with real objects, fingers, or a picture. Say the idea aloud, try one small example, and check it by counting or comparing again.
10 Worked Examples with Answers and Very-Beginner Explanations
Worked Example 1
Problem: What does One more with objects mean?
- Say the topic in simple words.
- Use objects, fingers, a drawing, or a number example.
- Tell what you notice.
Very beginner explanation: One more with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One more with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Worked Example 2
Problem: Show one small example of One more with objects.
- Choose small numbers or a simple shape/object.
- Make a model or drawing.
- Describe what the model shows.
Very beginner explanation: One more with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: A correct small model or drawing can show the meaning of One more with objects.
Worked Example 3
Problem: Which tool could help with One more with objects?
- Think about counters, fingers, a ten frame, number line, picture, table, or real object.
- Choose the tool that makes the idea easiest to see.
Very beginner explanation: One more with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Use a simple tool that lets you see and check the quantities or shapes.
Worked Example 4
Problem: How can you check your work in One more with objects?
- Look at the objects, drawing, or numbers again.
- Count or compare one more time.
- Make sure the answer matches the question.
Very beginner explanation: One more with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Check by recounting, comparing, or using a second simple model.
Worked Example 5
Problem: Where might you use One more with objects in everyday life?
- Think about toys, snacks, books, classroom objects, calendars, shapes, or money.
- Choose one situation.
- Explain how the math helps.
Very beginner explanation: One more with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One more with objects can help with a simple everyday task such as counting, sharing, comparing, measuring, organizing, or deciding.
Worked Example 6
Problem: What is one more than 6?
- Start at 6.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 7
Worked Example 7
Problem: What is one more than 12?
- Start at 12.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 13
Worked Example 8
Problem: What is one more than 19?
- Start at 19.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 20
Worked Example 9
Problem: What is one more than 27?
- Start at 27.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 28
Worked Example 10
Problem: What is one more than 44?
- Start at 44.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 45
Practice Exercise
Create one small question about One more with objects. Show it with objects, a picture, or numbers, then check by counting or comparing again.
7.2 One less with objects
One less with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Beginner Note
Start with real objects, fingers, or a picture. Say the idea aloud, try one small example, and check it by counting or comparing again.
10 Worked Examples with Answers and Very-Beginner Explanations
Worked Example 1
Problem: What does One less with objects mean?
- Say the topic in simple words.
- Use objects, fingers, a drawing, or a number example.
- Tell what you notice.
Very beginner explanation: One less with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One less with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Worked Example 2
Problem: Show one small example of One less with objects.
- Choose small numbers or a simple shape/object.
- Make a model or drawing.
- Describe what the model shows.
Very beginner explanation: One less with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: A correct small model or drawing can show the meaning of One less with objects.
Worked Example 3
Problem: Which tool could help with One less with objects?
- Think about counters, fingers, a ten frame, number line, picture, table, or real object.
- Choose the tool that makes the idea easiest to see.
Very beginner explanation: One less with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Use a simple tool that lets you see and check the quantities or shapes.
Worked Example 4
Problem: How can you check your work in One less with objects?
- Look at the objects, drawing, or numbers again.
- Count or compare one more time.
- Make sure the answer matches the question.
Very beginner explanation: One less with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Check by recounting, comparing, or using a second simple model.
Worked Example 5
Problem: Where might you use One less with objects in everyday life?
- Think about toys, snacks, books, classroom objects, calendars, shapes, or money.
- Choose one situation.
- Explain how the math helps.
Very beginner explanation: One less with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One less with objects can help with a simple everyday task such as counting, sharing, comparing, measuring, organizing, or deciding.
Worked Example 6
Problem: What is one less than 6?
- Start at 6.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 5
Worked Example 7
Problem: What is one less than 12?
- Start at 12.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 11
Worked Example 8
Problem: What is one less than 19?
- Start at 19.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 18
Worked Example 9
Problem: What is one less than 27?
- Start at 27.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 26
Worked Example 10
Problem: What is one less than 44?
- Start at 44.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 43
Practice Exercise
Create one small question about One less with objects. Show it with objects, a picture, or numbers, then check by counting or comparing again.
7.3 One more on a number line
One more on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Beginner Note
Start with real objects, fingers, or a picture. Say the idea aloud, try one small example, and check it by counting or comparing again.
10 Worked Examples with Answers and Very-Beginner Explanations
Worked Example 1
Problem: What does One more on a number line mean?
- Say the topic in simple words.
- Use objects, fingers, a drawing, or a number example.
- Tell what you notice.
Very beginner explanation: One more on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One more on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Worked Example 2
Problem: Show one small example of One more on a number line.
- Choose small numbers or a simple shape/object.
- Make a model or drawing.
- Describe what the model shows.
Very beginner explanation: One more on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: A correct small model or drawing can show the meaning of One more on a number line.
Worked Example 3
Problem: Which tool could help with One more on a number line?
- Think about counters, fingers, a ten frame, number line, picture, table, or real object.
- Choose the tool that makes the idea easiest to see.
Very beginner explanation: One more on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Use a simple tool that lets you see and check the quantities or shapes.
Worked Example 4
Problem: How can you check your work in One more on a number line?
- Look at the objects, drawing, or numbers again.
- Count or compare one more time.
- Make sure the answer matches the question.
Very beginner explanation: One more on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Check by recounting, comparing, or using a second simple model.
Worked Example 5
Problem: Where might you use One more on a number line in everyday life?
- Think about toys, snacks, books, classroom objects, calendars, shapes, or money.
- Choose one situation.
- Explain how the math helps.
Very beginner explanation: One more on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One more on a number line can help with a simple everyday task such as counting, sharing, comparing, measuring, organizing, or deciding.
Worked Example 6
Problem: What is one more than 6?
- Start at 6.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 7
Worked Example 7
Problem: What is one more than 12?
- Start at 12.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 13
Worked Example 8
Problem: What is one more than 19?
- Start at 19.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 20
Worked Example 9
Problem: What is one more than 27?
- Start at 27.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 28
Worked Example 10
Problem: What is one more than 44?
- Start at 44.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 45
Practice Exercise
Create one small question about One more on a number line. Show it with objects, a picture, or numbers, then check by counting or comparing again.
7.4 One less on a number line
One less on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Beginner Note
Start with real objects, fingers, or a picture. Say the idea aloud, try one small example, and check it by counting or comparing again.
10 Worked Examples with Answers and Very-Beginner Explanations
Worked Example 1
Problem: What does One less on a number line mean?
- Say the topic in simple words.
- Use objects, fingers, a drawing, or a number example.
- Tell what you notice.
Very beginner explanation: One less on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One less on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Worked Example 2
Problem: Show one small example of One less on a number line.
- Choose small numbers or a simple shape/object.
- Make a model or drawing.
- Describe what the model shows.
Very beginner explanation: One less on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: A correct small model or drawing can show the meaning of One less on a number line.
Worked Example 3
Problem: Which tool could help with One less on a number line?
- Think about counters, fingers, a ten frame, number line, picture, table, or real object.
- Choose the tool that makes the idea easiest to see.
Very beginner explanation: One less on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Use a simple tool that lets you see and check the quantities or shapes.
Worked Example 4
Problem: How can you check your work in One less on a number line?
- Look at the objects, drawing, or numbers again.
- Count or compare one more time.
- Make sure the answer matches the question.
Very beginner explanation: One less on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Check by recounting, comparing, or using a second simple model.
Worked Example 5
Problem: Where might you use One less on a number line in everyday life?
- Think about toys, snacks, books, classroom objects, calendars, shapes, or money.
- Choose one situation.
- Explain how the math helps.
Very beginner explanation: One less on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One less on a number line can help with a simple everyday task such as counting, sharing, comparing, measuring, organizing, or deciding.
Worked Example 6
Problem: What is one less than 6?
- Start at 6.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 5
Worked Example 7
Problem: What is one less than 12?
- Start at 12.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 11
Worked Example 8
Problem: What is one less than 19?
- Start at 19.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 18
Worked Example 9
Problem: What is one less than 27?
- Start at 27.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 26
Worked Example 10
Problem: What is one less than 44?
- Start at 44.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 43
Practice Exercise
Create one small question about One less on a number line. Show it with objects, a picture, or numbers, then check by counting or comparing again.
7.5 One more within 20
One more within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Beginner Note
Start with real objects, fingers, or a picture. Say the idea aloud, try one small example, and check it by counting or comparing again.
10 Worked Examples with Answers and Very-Beginner Explanations
Worked Example 1
Problem: What does One more within 20 mean?
- Say the topic in simple words.
- Use objects, fingers, a drawing, or a number example.
- Tell what you notice.
Very beginner explanation: One more within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One more within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Worked Example 2
Problem: Show one small example of One more within 20.
- Choose small numbers or a simple shape/object.
- Make a model or drawing.
- Describe what the model shows.
Very beginner explanation: One more within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: A correct small model or drawing can show the meaning of One more within 20.
Worked Example 3
Problem: Which tool could help with One more within 20?
- Think about counters, fingers, a ten frame, number line, picture, table, or real object.
- Choose the tool that makes the idea easiest to see.
Very beginner explanation: One more within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Use a simple tool that lets you see and check the quantities or shapes.
Worked Example 4
Problem: How can you check your work in One more within 20?
- Look at the objects, drawing, or numbers again.
- Count or compare one more time.
- Make sure the answer matches the question.
Very beginner explanation: One more within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Check by recounting, comparing, or using a second simple model.
Worked Example 5
Problem: Where might you use One more within 20 in everyday life?
- Think about toys, snacks, books, classroom objects, calendars, shapes, or money.
- Choose one situation.
- Explain how the math helps.
Very beginner explanation: One more within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One more within 20 can help with a simple everyday task such as counting, sharing, comparing, measuring, organizing, or deciding.
Worked Example 6
Problem: What is one more than 6?
- Start at 6.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 7
Worked Example 7
Problem: What is one more than 12?
- Start at 12.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 13
Worked Example 8
Problem: What is one more than 19?
- Start at 19.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 20
Worked Example 9
Problem: What is one more than 27?
- Start at 27.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 28
Worked Example 10
Problem: What is one more than 44?
- Start at 44.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 45
Practice Exercise
Create one small question about One more within 20. Show it with objects, a picture, or numbers, then check by counting or comparing again.
7.6 One less within 20
One less within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Beginner Note
Start with real objects, fingers, or a picture. Say the idea aloud, try one small example, and check it by counting or comparing again.
10 Worked Examples with Answers and Very-Beginner Explanations
Worked Example 1
Problem: What does One less within 20 mean?
- Say the topic in simple words.
- Use objects, fingers, a drawing, or a number example.
- Tell what you notice.
Very beginner explanation: One less within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One less within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Worked Example 2
Problem: Show one small example of One less within 20.
- Choose small numbers or a simple shape/object.
- Make a model or drawing.
- Describe what the model shows.
Very beginner explanation: One less within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: A correct small model or drawing can show the meaning of One less within 20.
Worked Example 3
Problem: Which tool could help with One less within 20?
- Think about counters, fingers, a ten frame, number line, picture, table, or real object.
- Choose the tool that makes the idea easiest to see.
Very beginner explanation: One less within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Use a simple tool that lets you see and check the quantities or shapes.
Worked Example 4
Problem: How can you check your work in One less within 20?
- Look at the objects, drawing, or numbers again.
- Count or compare one more time.
- Make sure the answer matches the question.
Very beginner explanation: One less within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Check by recounting, comparing, or using a second simple model.
Worked Example 5
Problem: Where might you use One less within 20 in everyday life?
- Think about toys, snacks, books, classroom objects, calendars, shapes, or money.
- Choose one situation.
- Explain how the math helps.
Very beginner explanation: One less within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One less within 20 can help with a simple everyday task such as counting, sharing, comparing, measuring, organizing, or deciding.
Worked Example 6
Problem: What is one less than 6?
- Start at 6.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 5
Worked Example 7
Problem: What is one less than 12?
- Start at 12.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 11
Worked Example 8
Problem: What is one less than 19?
- Start at 19.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 18
Worked Example 9
Problem: What is one less than 27?
- Start at 27.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 26
Worked Example 10
Problem: What is one less than 44?
- Start at 44.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 43
Practice Exercise
Create one small question about One less within 20. Show it with objects, a picture, or numbers, then check by counting or comparing again.
7.7 One more within 50
One more within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Beginner Note
Start with real objects, fingers, or a picture. Say the idea aloud, try one small example, and check it by counting or comparing again.
10 Worked Examples with Answers and Very-Beginner Explanations
Worked Example 1
Problem: What does One more within 50 mean?
- Say the topic in simple words.
- Use objects, fingers, a drawing, or a number example.
- Tell what you notice.
Very beginner explanation: One more within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One more within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Worked Example 2
Problem: Show one small example of One more within 50.
- Choose small numbers or a simple shape/object.
- Make a model or drawing.
- Describe what the model shows.
Very beginner explanation: One more within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: A correct small model or drawing can show the meaning of One more within 50.
Worked Example 3
Problem: Which tool could help with One more within 50?
- Think about counters, fingers, a ten frame, number line, picture, table, or real object.
- Choose the tool that makes the idea easiest to see.
Very beginner explanation: One more within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Use a simple tool that lets you see and check the quantities or shapes.
Worked Example 4
Problem: How can you check your work in One more within 50?
- Look at the objects, drawing, or numbers again.
- Count or compare one more time.
- Make sure the answer matches the question.
Very beginner explanation: One more within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Check by recounting, comparing, or using a second simple model.
Worked Example 5
Problem: Where might you use One more within 50 in everyday life?
- Think about toys, snacks, books, classroom objects, calendars, shapes, or money.
- Choose one situation.
- Explain how the math helps.
Very beginner explanation: One more within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One more within 50 can help with a simple everyday task such as counting, sharing, comparing, measuring, organizing, or deciding.
Worked Example 6
Problem: What is one more than 6?
- Start at 6.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 7
Worked Example 7
Problem: What is one more than 12?
- Start at 12.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 13
Worked Example 8
Problem: What is one more than 19?
- Start at 19.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 20
Worked Example 9
Problem: What is one more than 27?
- Start at 27.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 28
Worked Example 10
Problem: What is one more than 44?
- Start at 44.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 45
Practice Exercise
Create one small question about One more within 50. Show it with objects, a picture, or numbers, then check by counting or comparing again.
7.8 One less within 50
One less within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Beginner Note
Start with real objects, fingers, or a picture. Say the idea aloud, try one small example, and check it by counting or comparing again.
10 Worked Examples with Answers and Very-Beginner Explanations
Worked Example 1
Problem: What does One less within 50 mean?
- Say the topic in simple words.
- Use objects, fingers, a drawing, or a number example.
- Tell what you notice.
Very beginner explanation: One less within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One less within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Worked Example 2
Problem: Show one small example of One less within 50.
- Choose small numbers or a simple shape/object.
- Make a model or drawing.
- Describe what the model shows.
Very beginner explanation: One less within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: A correct small model or drawing can show the meaning of One less within 50.
Worked Example 3
Problem: Which tool could help with One less within 50?
- Think about counters, fingers, a ten frame, number line, picture, table, or real object.
- Choose the tool that makes the idea easiest to see.
Very beginner explanation: One less within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Use a simple tool that lets you see and check the quantities or shapes.
Worked Example 4
Problem: How can you check your work in One less within 50?
- Look at the objects, drawing, or numbers again.
- Count or compare one more time.
- Make sure the answer matches the question.
Very beginner explanation: One less within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Check by recounting, comparing, or using a second simple model.
Worked Example 5
Problem: Where might you use One less within 50 in everyday life?
- Think about toys, snacks, books, classroom objects, calendars, shapes, or money.
- Choose one situation.
- Explain how the math helps.
Very beginner explanation: One less within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One less within 50 can help with a simple everyday task such as counting, sharing, comparing, measuring, organizing, or deciding.
Worked Example 6
Problem: What is one less than 6?
- Start at 6.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 5
Worked Example 7
Problem: What is one less than 12?
- Start at 12.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 11
Worked Example 8
Problem: What is one less than 19?
- Start at 19.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 18
Worked Example 9
Problem: What is one less than 27?
- Start at 27.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 26
Worked Example 10
Problem: What is one less than 44?
- Start at 44.
- Count back 1.
Very beginner explanation: One less means move back one number.
Answer: 43
Practice Exercise
Create one small question about One less within 50. Show it with objects, a picture, or numbers, then check by counting or comparing again.
7.9 Story problems with one more or less
Story problems with one more or less helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Beginner Note
Start with real objects, fingers, or a picture. Say the idea aloud, try one small example, and check it by counting or comparing again.
10 Worked Examples with Answers and Very-Beginner Explanations
Worked Example 1
Problem: What does Story problems with one more or less mean?
- Say the topic in simple words.
- Use objects, fingers, a drawing, or a number example.
- Tell what you notice.
Very beginner explanation: Story problems with one more or less helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Story problems with one more or less helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Worked Example 2
Problem: Show one small example of Story problems with one more or less.
- Choose small numbers or a simple shape/object.
- Make a model or drawing.
- Describe what the model shows.
Very beginner explanation: Story problems with one more or less helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: A correct small model or drawing can show the meaning of Story problems with one more or less.
Worked Example 3
Problem: Which tool could help with Story problems with one more or less?
- Think about counters, fingers, a ten frame, number line, picture, table, or real object.
- Choose the tool that makes the idea easiest to see.
Very beginner explanation: Story problems with one more or less helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Use a simple tool that lets you see and check the quantities or shapes.
Worked Example 4
Problem: How can you check your work in Story problems with one more or less?
- Look at the objects, drawing, or numbers again.
- Count or compare one more time.
- Make sure the answer matches the question.
Very beginner explanation: Story problems with one more or less helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Check by recounting, comparing, or using a second simple model.
Worked Example 5
Problem: Where might you use Story problems with one more or less in everyday life?
- Think about toys, snacks, books, classroom objects, calendars, shapes, or money.
- Choose one situation.
- Explain how the math helps.
Very beginner explanation: Story problems with one more or less helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Story problems with one more or less can help with a simple everyday task such as counting, sharing, comparing, measuring, organizing, or deciding.
Worked Example 6
Problem: What is one more than 6?
- Start at 6.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 7
Worked Example 7
Problem: What is one more than 12?
- Start at 12.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 13
Worked Example 8
Problem: What is one more than 19?
- Start at 19.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 20
Worked Example 9
Problem: What is one more than 27?
- Start at 27.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 28
Worked Example 10
Problem: What is one more than 44?
- Start at 44.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 45
Practice Exercise
Create one small question about Story problems with one more or less. Show it with objects, a picture, or numbers, then check by counting or comparing again.
7.10 One more and one less review
One more and one less review helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Beginner Note
Start with real objects, fingers, or a picture. Say the idea aloud, try one small example, and check it by counting or comparing again.
10 Worked Examples with Answers and Very-Beginner Explanations
Worked Example 1
Problem: What does One more and one less review mean?
- Say the topic in simple words.
- Use objects, fingers, a drawing, or a number example.
- Tell what you notice.
Very beginner explanation: One more and one less review helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One more and one less review helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Worked Example 2
Problem: Show one small example of One more and one less review.
- Choose small numbers or a simple shape/object.
- Make a model or drawing.
- Describe what the model shows.
Very beginner explanation: One more and one less review helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: A correct small model or drawing can show the meaning of One more and one less review.
Worked Example 3
Problem: Which tool could help with One more and one less review?
- Think about counters, fingers, a ten frame, number line, picture, table, or real object.
- Choose the tool that makes the idea easiest to see.
Very beginner explanation: One more and one less review helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Use a simple tool that lets you see and check the quantities or shapes.
Worked Example 4
Problem: How can you check your work in One more and one less review?
- Look at the objects, drawing, or numbers again.
- Count or compare one more time.
- Make sure the answer matches the question.
Very beginner explanation: One more and one less review helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: Check by recounting, comparing, or using a second simple model.
Worked Example 5
Problem: Where might you use One more and one less review in everyday life?
- Think about toys, snacks, books, classroom objects, calendars, shapes, or money.
- Choose one situation.
- Explain how the math helps.
Very beginner explanation: One more and one less review helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Answer: One more and one less review can help with a simple everyday task such as counting, sharing, comparing, measuring, organizing, or deciding.
Worked Example 6
Problem: What is one more than 6?
- Start at 6.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 7
Worked Example 7
Problem: What is one more than 12?
- Start at 12.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 13
Worked Example 8
Problem: What is one more than 19?
- Start at 19.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 20
Worked Example 9
Problem: What is one more than 27?
- Start at 27.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 28
Worked Example 10
Problem: What is one more than 44?
- Start at 44.
- Count forward 1.
Very beginner explanation: One more means move forward one number.
Answer: 45
Practice Exercise
Create one small question about One more and one less review. Show it with objects, a picture, or numbers, then check by counting or comparing again.
Chapter Notes, Practice, and Common Mistakes
Chapter Notes
- Read or listen to the question before solving.
- Use objects, a drawing, ten frame, number line, table, graph, or simple number sentence when useful.
- Explain your thinking and check by counting, comparing, or using another simple model.
Extra Practice
- Create and solve one original problem about One more with objects.
- Create and solve one original problem about One less with objects.
- Create and solve one original problem about One more on a number line.
- Create and solve one original problem about One less on a number line.
- Create and solve one original problem about One more within 20.
- Create and solve one original problem about One less within 20.
Common Mistakes
- Skipping the meaning and trying to memorize a rule only.
- Using the wrong operation because the question was not read completely.
- Ignoring units, labels, place values, or the context of the problem.
- Not estimating or checking whether the final answer is reasonable.
30 Review Questions and Answers
Q1. What is the main idea in One more with objects?
Answer: One more with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Q2. What is the main idea in One less with objects?
Answer: One less with objects helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Q3. What is the main idea in One more on a number line?
Answer: One more on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Q4. What is the main idea in One less on a number line?
Answer: One less on a number line helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Q5. What is the main idea in One more within 20?
Answer: One more within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Q6. What is the main idea in One less within 20?
Answer: One less within 20 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Q7. What is the main idea in One more within 50?
Answer: One more within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Q8. What is the main idea in One less within 50?
Answer: One less within 50 helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Q9. What is the main idea in Story problems with one more or less?
Answer: Story problems with one more or less helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Q10. What is the main idea in One more and one less review?
Answer: One more and one less review helps Grade 1 learners build strong number sense with small numbers, objects, drawings, and number lines.
Q11. Why is it useful to use counters or drawings?
Answer: They make the quantities visible and help you understand before using only numbers.
Q12. Why should you count carefully?
Answer: Careful counting means each object is counted once and no object is missed.
Q13. What can you do if a problem feels hard?
Answer: Use smaller numbers, draw a picture, use objects, and solve one small step at a time.
Q14. Why should both sides of an equals sign match?
Answer: The equals sign means the two sides have the same value.
Q15. How can a number line help?
Answer: It shows number order and can help you count forward or backward.
Q16. How can a ten frame help?
Answer: It organizes objects into groups that make numbers and addition easier to see.
Q17. Why are equal shares important?
Answer: Equal shares make fair groups or equal parts.
Q18. How do patterns help us predict?
Answer: A pattern rule tells us what should come next.
Q19. Why do we label a graph or table?
Answer: Labels tell us what the information represents.
Q20. How can you describe a shape?
Answer: Talk about its sides, corners, flat or curved surfaces, and other visible attributes.
Q21. How can you compare two objects?
Answer: Choose one attribute, such as length, mass, or capacity, and compare that same attribute.
Q22. Why is a calendar useful?
Answer: It organizes days, weeks, months, dates, and events.
Q23. Why does money have different values?
Answer: Different coins and bills represent different amounts of money.
Q24. Why should you explain your answer?
Answer: Explaining shows how you thought about the problem and helps you check your reasoning.
Q25. What should you do after a mistake?
Answer: Look at the step again, fix it, and try a similar example.
Q26. How can you be a confident math learner?
Answer: Use positive self-talk, try a strategy, ask questions, and remember that mistakes help you learn.
Q27. When should you use a picture?
Answer: Use a picture when it helps you see quantities, shapes, positions, or a story problem.
Q28. When should you use objects?
Answer: Use objects when you want to count, join, take away, share, sort, or compare in a hands-on way.
Q29. How can you check addition?
Answer: Recount the combined objects or use another model.
Q30. How can you check subtraction?
Answer: Put the taken-away part and the part left back together to see if they make the starting amount.