Related subtraction facts

Key notes:

What are Related Subtraction Facts?

  • Related subtraction facts come from the same group of numbers.
  • They are connected to addition facts.
  • They help us understand how numbers work together.

🔹 Fact Family (Number Family)

  • A fact family has 3 numbers.
  • These numbers make 2 addition facts and 2 subtraction facts.

👉 Example: Numbers 3, 4, 7

  • Addition facts:
    • 3 + 4 = 7
    • 4 + 3 = 7
  • Subtraction facts:
    • 7 − 3 = 4
    • 7 − 4 = 3

🔹 Key Idea

  • Subtraction is the opposite of addition.
  • If you know one addition fact, you can find related subtraction facts.

👉 Example:
If 5 + 2 = 7, then:

  • 7 − 5 = 2
  • 7 − 2 = 5

🔹 Using Pictures or Objects

  • Use fingers, toys, or drawings to understand subtraction.
  • Take away objects to see what is left.

👉 Example:
🍎🍎🍎🍎🍎 (5 apples)
Take away 2 → 🍎🍎🍎 (3 left)
So, 5 − 2 = 3

🔹 Missing Number Practice

  • Fill in the blanks using related facts:

👉 Example:
6 − ___ = 4 → Answer: 2
(Because 4 + 2 = 6)

🔹 Why It Is Important

  • Helps in quick calculations
  • Builds strong number sense
  • Makes math easy and fun

🎯 Quick Tips for Students

  • Always think: “What number is missing?”
  • Use addition to check subtraction
  • Practice with small numbers (up to 20)

  • Related subtraction facts use the same numbers. To find the related subtraction fact, swap the numbers after the minus sign and the equals sign.

Learn with an example

🍄Which is the related subtraction fact for 10 − 3 = 7?

  • 7 − 3 = 4
  • 10 − 8 = 2
  • 10 − 6 = 4
  • 10 − 7 = 3

This is a subtraction fact.

  • 10 − 3 = 7

This is the related fact.

  • 10 − 7 = 3

Notice how the 3 and the 7 changed places.

🍄Which is the related subtraction fact for 6 − 5 = 1?

  • 6 − 1 = 5
  • 10 − 1 = 9
  • 5 − 1 = 4
  • 6 − 0 = 6

This is a subtraction fact.

  • 6 − 5 = 1

This is the related fact.

  • 6 − 1 = 5

Notice how the 5 and the 1 changed places.

🍄Which is the related subtraction fact for 9 − 2 = 7?

  • 9 − 6 = 3
  • 8 − 7 = 1
  • 9 − 7 = 2
  • 7 − 2 = 5

This is a subtraction fact.

  • 9 − 2 = 7

This is the related fact.

  • 9 − 7 = 2

Notice how the 2 and the 7 changed places.

Let’s practice!