Learn on PengiSaxon Math, Intermediate 4Chapter 1: Lessons 1–10, Investigation 1

Lesson 6: Review of Subtraction

In this Grade 4 Saxon Math lesson, students review subtraction concepts including the meaning of the difference, how to check subtraction answers using inverse operations, and how to identify and write addition and subtraction fact families. The lesson also introduces the terms expression and equation as part of building math vocabulary in Chapter 1.

Section 1

📘 Review of Subtraction

New Concept

When we subtract one number from another number, the answer is called the difference.

Why it matters

Subtraction isn't just about taking away; it's the 'undo' button for addition, a concept at the heart of mathematical problem-solving. Mastering this relationship is your first step toward balancing complex equations and unlocking the secrets of algebra.

What’s next

Next, you’ll explore this relationship by creating fact families and using addition to check your subtraction work, solidifying this foundational skill.

Section 2

Subtract

Property

When we subtract, we separate one group into two groups. To take away two from six, we subtract.

6−2=46 - 2 = 4

Example

For 14−8=614 - 8 = 6, you can check your answer by adding up: 6+8=146 + 8 = 14. For 15−7=815 - 7 = 8, you can check with 8+7=158 + 7 = 15.

Explanation

Think of subtraction as the 'take-away' game. You start with a whole group, like six cookies, and separate it by taking some away. It is the opposite of addition, so you can check your answer by adding back what you took away to see if you get the original amount!

Section 3

Difference

Property

When we subtract one number from another number, the answer is called the difference.

Example

In the problem 12−5=712 - 5 = 7, the number 7 is the difference. To find the difference between twenty dollars and twelve dollars, you calculate 20−12=820 - 12 = 8.

Explanation

The 'difference' is just the fancy math name for the answer you get after subtracting! If your brother has ten dollars and you have seven dollars, the difference is three dollars. It is what is left over or the amount between the two numbers. It is the result of a subtraction problem.

Section 4

Fact family

Property

A fact family is a group of three numbers that can be arranged to form four facts.

Example

The numbers 3, 5, and 8 form a fact family: 3+5=83+5=8, 5+3=85+3=8, 8−5=38-5=3, and 8−3=58-3=5. For the numbers 5, 6, and 11, the fact family is: 5+6=115+6=11, 6+5=116+5=11, 11−6=511-6=5, and 11−5=611-5=6.

Explanation

Think of a fact family like a little gang of numbers that always hang out together. Using just three numbers, you can write two addition and two subtraction problems that are all related. It is a great way to see how addition and subtraction are just reverse versions of each other!

Section 5

Expression

Property

An expression is a number, a letter, or a combination of numbers and letters. Expressions usually contain one or more operation symbols.

Example

The number 7 by itself is an expression. A combination like 14−514 - 5 is an expression. Using a letter, w+8w + 8 is also an expression.

Explanation

An expression is like a math phrase or a recipe—it is a mix of numbers, letters, and operation signs. Think of it as a question or a statement without the final answer, because it does not have an equals sign. An expression is a mathematical phrase that can be a number, a variable, or a combination.

Book overview

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Chapter 1: Lessons 1–10, Investigation 1

  1. Lesson 1

    Lesson 1: Review of Addition

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  2. Lesson 2

    Lesson 2: Missing Addends

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  3. Lesson 3

    Lesson 3: Sequences

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  4. Lesson 4

    Lesson 4: Place Value, Activity Comparing Money Amounts

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  5. Lesson 5

    Lesson 5: Ordinal Numbers, Months of the Year

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  6. Lesson 6Current

    Lesson 6: Review of Subtraction

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  7. Lesson 7

    Lesson 7: Writing Numbers Through 999

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  8. Lesson 8

    Lesson 8: Adding Money

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  9. Lesson 9

    Lesson 9: Adding with Regrouping

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  10. Lesson 10

    Lesson 10: Even and Odd Numbers

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  11. Lesson 11

    Lesson 11: Investigation 1 Number Lines, Activity Drawing Number Lines

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Lesson overview

Expand to review the lesson summary and core properties.

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Section 1

📘 Review of Subtraction

New Concept

When we subtract one number from another number, the answer is called the difference.

Why it matters

Subtraction isn't just about taking away; it's the 'undo' button for addition, a concept at the heart of mathematical problem-solving. Mastering this relationship is your first step toward balancing complex equations and unlocking the secrets of algebra.

What’s next

Next, you’ll explore this relationship by creating fact families and using addition to check your subtraction work, solidifying this foundational skill.

Section 2

Subtract

Property

When we subtract, we separate one group into two groups. To take away two from six, we subtract.

6−2=46 - 2 = 4

Example

For 14−8=614 - 8 = 6, you can check your answer by adding up: 6+8=146 + 8 = 14. For 15−7=815 - 7 = 8, you can check with 8+7=158 + 7 = 15.

Explanation

Think of subtraction as the 'take-away' game. You start with a whole group, like six cookies, and separate it by taking some away. It is the opposite of addition, so you can check your answer by adding back what you took away to see if you get the original amount!

Section 3

Difference

Property

When we subtract one number from another number, the answer is called the difference.

Example

In the problem 12−5=712 - 5 = 7, the number 7 is the difference. To find the difference between twenty dollars and twelve dollars, you calculate 20−12=820 - 12 = 8.

Explanation

The 'difference' is just the fancy math name for the answer you get after subtracting! If your brother has ten dollars and you have seven dollars, the difference is three dollars. It is what is left over or the amount between the two numbers. It is the result of a subtraction problem.

Section 4

Fact family

Property

A fact family is a group of three numbers that can be arranged to form four facts.

Example

The numbers 3, 5, and 8 form a fact family: 3+5=83+5=8, 5+3=85+3=8, 8−5=38-5=3, and 8−3=58-3=5. For the numbers 5, 6, and 11, the fact family is: 5+6=115+6=11, 6+5=116+5=11, 11−6=511-6=5, and 11−5=611-5=6.

Explanation

Think of a fact family like a little gang of numbers that always hang out together. Using just three numbers, you can write two addition and two subtraction problems that are all related. It is a great way to see how addition and subtraction are just reverse versions of each other!

Section 5

Expression

Property

An expression is a number, a letter, or a combination of numbers and letters. Expressions usually contain one or more operation symbols.

Example

The number 7 by itself is an expression. A combination like 14−514 - 5 is an expression. Using a letter, w+8w + 8 is also an expression.

Explanation

An expression is like a math phrase or a recipe—it is a mix of numbers, letters, and operation signs. Think of it as a question or a statement without the final answer, because it does not have an equals sign. An expression is a mathematical phrase that can be a number, a variable, or a combination.

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 1: Lessons 1–10, Investigation 1

  1. Lesson 1

    Lesson 1: Review of Addition

    LearnPractice
  2. Lesson 2

    Lesson 2: Missing Addends

    LearnPractice
  3. Lesson 3

    Lesson 3: Sequences

    LearnPractice
  4. Lesson 4

    Lesson 4: Place Value, Activity Comparing Money Amounts

    LearnPractice
  5. Lesson 5

    Lesson 5: Ordinal Numbers, Months of the Year

    LearnPractice
  6. Lesson 6Current

    Lesson 6: Review of Subtraction

    LearnPractice
  7. Lesson 7

    Lesson 7: Writing Numbers Through 999

    LearnPractice
  8. Lesson 8

    Lesson 8: Adding Money

    LearnPractice
  9. Lesson 9

    Lesson 9: Adding with Regrouping

    LearnPractice
  10. Lesson 10

    Lesson 10: Even and Odd Numbers

    LearnPractice
  11. Lesson 11

    Lesson 11: Investigation 1 Number Lines, Activity Drawing Number Lines

    LearnPractice