Subtraction fact: A basic subtraction equation with numbers within 10 that should be memorized for quick recall.
Note: Subtraction facts within 10 form the foundation for more complex subtraction problems and mental math.
- Start with the minuend (the first number)
- Count backward by the subtrahend (the second number)
- Count how many you have left
We begin at 5 on the number line
Move 2 spaces to the left: 5 → 4 → 3
We land on 3, so 5 - 2 = 3
5 - 2 = 3
• Count back strategy: Move left on number line by subtrahend
• Number relationship: 5 is made up of 2 and 3
• Verification: Add back: 3 + 2 = 5 ✓
• Practice Tip: Count backward: 5, 4, 3 (stop after 2 counts)
- 4 - 1 = 3 (start at 4, count back 1)
- 6 - 3 = 3 (start at 6, count back 3)
- 8 - 5 = 3 (start at 8, count back 5)
- Use your fingers to count backward
- Think of subtraction as "taking away"
- Always verify by adding the answer back to the subtracted number
Q: Can I subtract a bigger number from a smaller number?
A: Not yet! In 1st grade, we only subtract smaller numbers from bigger numbers.
Q: What if I count wrong?
A: Count slowly and carefully. You can also use your fingers to help.
Number bond: A visual representation showing how numbers can be split into parts that make up the whole number.
Note: Number bonds help understand the relationship between addition and subtraction, showing that 7 can be broken into 3 and 4.
- Identify the whole number (minuend)
- Identify one part (subtrahend)
- Find the missing part (difference)
7 is the whole number we start with
3 is the part we are taking away
What part combines with 3 to make 7? Answer: 4
7 - 3 = 4
• Part-whole relationship: 7 = 3 + 4, so 7 - 3 = 4
• Addition connection: Subtraction reverses addition
• Number bond: Shows how numbers relate to each other
• Practice Tip: Remember: if 3 + 4 = 7, then 7 - 3 = 4
- 5 - 2 = 3 because 2 + 3 = 5
- 8 - 5 = 3 because 5 + 3 = 8
- 9 - 4 = 5 because 4 + 5 = 9
- Think of subtraction as finding a missing part
- Use addition facts to help with subtraction
- If you know 4 + 3 = 7, then 7 - 4 = 3
Q: How are addition and subtraction connected?
A: They are opposite operations. If 3 + 4 = 7, then 7 - 3 = 4 and 7 - 4 = 3.
Q: What are number bonds good for?
A: They help you see how numbers fit together and make mental math easier.
Count back strategy: Starting from the minuend and counting backward by the number of steps equal to the subtrahend.
Note: This strategy helps build number sense and is a bridge to mental subtraction without physical counting.
- Start with the minuend (first number)
- Count backward one number at a time
- Stop after counting back the number of steps equal to the subtrahend
We begin counting from 9
9 → 8 → 7 → 6 → 5 (that's 4 steps)
We land on 5, so 9 - 4 = 5
9 - 4 = 5
• Sequential counting: Count each number as you move back
• Step tracking: Keep track of how many steps you've taken
• Stopping rule: Stop after the number of steps equals the subtrahend
• Practice Tip: Use fingers to track the steps: 9, 8, 7, 6, 5
- 8 - 3 = 5 (8, 7, 6, 5)
- 7 - 2 = 5 (7, 6, 5)
- 6 - 4 = 2 (6, 5, 4, 3, 2)
- Use your fingers to keep track of steps
- Count out loud to stay focused
- Start with the larger number and count backward
Q: What if I lose track while counting back?
A: Use your fingers to track each step, or start over and count more slowly.
Q: Can I count forward instead?
A: Counting back is the subtraction strategy. Counting forward is for addition.
Missing number subtraction: Finding the unknown subtrahend in a subtraction equation where the minuend and difference are known.
Note: This helps develop algebraic thinking early by understanding the relationship between the parts of a subtraction equation.
- Start with the minuend (8)
- Think about what needs to be subtracted to get the difference (3)
- Count how many steps from difference back to minuend
We have 8 - ? = 3, so we need to find what number subtracted from 8 gives us 3
8 is made up of 3 and another number. If 8 = 3 + ?, then ? = 8 - 3 = 5
Check: 8 - 5 = 3 ✓
The missing number is 5.
• Relationship understanding: Minuend - Subtrahend = Difference
• Reversibility: Difference + Subtrahend = Minuend
• Verification: Always check your answer by substituting back
• Practice Tip: Think: "What number added to 3 makes 8?" Answer: 5
- 7 - ? = 4, so ? = 3 because 7 - 3 = 4
- 9 - ? = 2, so ? = 7 because 9 - 7 = 2
- 6 - ? = 1, so ? = 5 because 6 - 5 = 1
- Think of subtraction as "what to take away"
- Use addition to check: if 8 - ? = 3, then 3 + ? = 8
- Count from the answer to the starting number
Q: How do I know which number is missing?
A: Look at the equation format: Minuend - Subtrahend = Difference. Usually the subtrahend is missing.
Q: Can the missing number be bigger than the starting number?
A: No, in subtraction the number being subtracted must be equal to or less than the starting number.
Fact family: A group of related addition and subtraction facts that use the same three numbers.
Note: Fact families show the inverse relationship between addition and subtraction, helping students understand how operations connect.
- Identify the three numbers in the family (5, 3, 8)
- Create two addition facts
- Create two subtraction facts
From 5 + 3 = 8, our numbers are 5, 3, and 8
5 + 3 = 8 and 3 + 5 = 8 (commutative property)
8 - 3 = 5 and 8 - 5 = 3 (starting with the largest number)
The related subtraction facts are: 8 - 3 = 5 and 8 - 5 = 3
• Fact family principle: Three numbers create four related facts
• Inverse operations: Addition and subtraction reverse each other
• Commutative property: Order doesn't matter in addition
• Practice Tip: Always start subtraction facts with the largest number
- If 4 + 2 = 6: 2 + 4 = 6, 6 - 2 = 4, 6 - 4 = 2
- If 7 + 1 = 8: 1 + 7 = 8, 8 - 1 = 7, 8 - 7 = 1
- If 6 + 3 = 9: 3 + 6 = 9, 9 - 3 = 6, 9 - 6 = 3
- Always start subtraction facts with the biggest number
- Know one fact, and you know three others
- Fact families help with both addition and subtraction
Q: Why do we learn fact families?
A: They show how addition and subtraction are connected and help with mental math.
Q: Do all numbers make fact families?
A: Any three numbers that work in addition/subtraction can form a family.