Grade 1 · Operations · MAT-01-OPS-002
Subtraction Facts Within 10
Subtract within 10 using take-away, missing-part, and counting-back or think-addition strategies.
Learning objectives
What you should be able to do
- Subtract within 10 using take-away, missing-part, and counting-back or think-addition strategies.
- Use known addition facts to solve related subtraction facts.
- Explain subtraction results as differences or missing parts rather than isolated answers.
Prerequisite check
Make sure the foundation is ready.
Checks operation meaning.
Checks inverse part-whole reasoning.
Learn
Build the idea from meaning, not memorization.
Subtraction can be solved in more than one way
You can remove objects, count backward, find a missing part, or think of the related addition fact. Different strategies are useful for different numbers.
Think addition when facts are closely related
For 8−5, ask '5 plus what makes 8?' Since 5+3=8, the difference is 3. This connects subtraction to known addition facts.
Subtracting one and subtracting zero have clear structures
Subtracting one gives the previous whole number. Subtracting zero leaves the starting number unchanged. Subtracting a number from itself leaves zero.
Fluency grows from relationships
If 7−3=4 is known, then 7−4=3 is a related part-whole fact. Learning these families reduces isolated memorization.
Interactive math lab
Change it. See what stays true.
Equation Balance
Adjust both sides. Equality means both expressions have the same value.
Balanced: both sides have equal value.
- take away
- think addition
- fact family
- subtract zero self
Worked examples
Twenty different ways to see the concept work.
3−1
2One less than three is two.
4−2
2Remove two from four.
5−1
4Subtract one to get previous number.
6−2
4Count back 5,4.
7−3
4Think 3+4=7.
8−5
3Think 5+3=8.
9−2
7Count back two.
10−4
6Think 4+6=10.
6−6
0Removing the whole leaves zero.
7−0
7Removing nothing leaves seven.
5−3
23+2=5.
8−4
4Half of eight is four; 4+4=8.
10−5
5Five and five make ten.
9−8
1Eight needs one more to make nine.
4−3
1Three plus one equals four.
7−5
2Five plus two equals seven.
10−1
9One less than ten is nine.
2−2
0A number minus itself is zero.
Explain 8−3 using addition.
3+5=8, so 8−3=5Addition identifies the missing part.
Explain relation between 7−3 and 7−4.
The two parts are 3 and 4Both come from 3+4=7.
Practice
Guided practice with hints
01Solve 6−1.
Hint: One less than six.
Answer: 5
02Solve 8−3.
Hint: Ask 3+?=8.
Answer: 5
03Solve 10−5.
Hint: Use the double 5+5.
Answer: 5
04Solve 7−0.
Hint: Nothing is removed.
Answer: 7
05Solve 9−8.
Hint: What plus 8 makes 9?
Answer: 1
06Solve 5−5.
Hint: All of the starting amount is removed.
Answer: 0
Practice
Independent practice
014−1
Answer: 3
026−3
Answer: 3
037−2
Answer: 5
048−6
Answer: 2
059−4
Answer: 5
0610−3
Answer: 7
075−0
Answer: 5
083−3
Answer: 0
Common mistakes
Learn to catch the error, not just the answer.
Start at the whole; each removed unit is one move to the previous number.
For close numbers such as 9−8, ask what must be added to 8 to make 9.
Check with addition: difference + subtracted part should rebuild the starting whole.
Applications & challenge
Use the idea beyond a single exercise.
Applications
- Track remaining items after small amounts are used or removed.
- Find missing quantities when a total and one part are known.
Challenge problems
Use addition to solve 9−6.
6+3=9, so 3.
If 4+3=7, name two subtraction facts.
7−4=3 and 7−3=4.
Why is 10−9 easier by think-addition?
Ask 9+?=10; the missing amount is 1.
Explain why 6−0=6 and 6−6=0 are different.
Subtracting none changes nothing; subtracting the entire amount leaves none.
Flashcards
Retrieve it from memory.
Flashcards
Card 1 of 6
Game mode
Fact Path: Subtract
Solve subtraction facts by choosing take-away, count-back, or think-addition.
Practice
Mastery check
015−2
Answer: 3
027−3
Answer: 4
038−5
Answer: 3
0410−4
Answer: 6
059−8
Answer: 1
066−0
Answer: 6
07Use addition to check 7−2=5.
Answer: 5+2=7
08What happens when a number subtracts itself?
Answer: The result is 0.
Terminology
Words to know
- subtraction fact
- A basic subtraction equation used frequently.
- difference
- The result of subtraction.
- think addition
- Solve subtraction by finding the addend needed to make the whole.
- fact family
- Related addition and subtraction facts using the same numbers.
Continue learning
Connected concepts
Curriculum references
Standards and instructional references
California Common Core State Standards for Mathematics — Grade 1 Operations & Algebraic Thinking
Grade 1 addition/subtraction fluency, properties, and strategy progression.