Subtraction Facts 0-20 - 2nd Grade Mathematics

Master basic subtraction facts from 0 to 20 through structured practice and memorization techniques.

Subtraction Facts 1-10 with Solutions
1 Minus Zero Facts
Fact Family 1
Practice minus zero facts: 10 - 0 = ?, 15 - 0 = ?, 18 - 0 = ?, 20 - 0 = ?
Difficulty: Beginner Time: ~2 minutes Skills: Basic Subtraction, Zero Property, Number Sense
Definition:

Minus zero facts: Subtraction facts where the subtrahend is 0. Any number minus 0 equals the original number.

Note: This is known as the zero property of subtraction. When you subtract zero from any number, you get the same number.

Step-by-step fact learning:
  1. Recognize that you're subtracting zero
  2. Understand that nothing is being taken away
  3. The answer is the same as the minuend
  4. Memorize this pattern: n - 0 = n
Problem 1: 10-0
10 - 0 = 10
Problem 2: 15-0
15 - 0 = 15
Problem 3: 18-0
18 - 0 = 18
Problem 4: 20-0
20 - 0 = 20
Step 1: For 10 - 0

When you take away 0 from 10, you still have 10

Step 2: For 15 - 0

When you take away 0 from 15, you still have 15

Step 3: For 18 - 0

When you take away 0 from 18, you still have 18

Step 4: For 20 - 0

When you take away 0 from 20, you still have 20

10 - 0 = 10, 15 - 0 = 15, 18 - 0 = 18, 20 - 0 = 20
Final answers:

10 - 0 = 10, 15 - 0 = 15, 18 - 0 = 18, 20 - 0 = 20

Applied rules:

• Zero property: Any number minus 0 equals itself

• Pattern recognition: n - 0 = n for any number n

• Conceptual understanding: Nothing taken away means nothing changes

• Practice Tip: This is the easiest subtraction fact family to memorize

2 Minus One Facts
Fact Family 2
Practice minus one facts: 12 - 1 = ?, 17 - 1 = ?, 19 - 1 = ?, 14 - 1 = ?
Difficulty: Beginner Time: ~2 minutes Skills: Basic Subtraction, Counting Back, Number Sense
Definition:

Minus one facts: Subtraction facts where the subtrahend is 1. The answer is always one less than the minuend.

Note: When you subtract 1 from any number, you get the number that comes just before it in counting order.

Step-by-step fact learning:
  1. Recognize that you're subtracting one
  2. Count back one from the minuend
  3. The answer is the previous number in counting order
  4. Memorize this pattern: n - 1 = (n-1)
Problem 1: 12-1
12 - 1 = 11
Problem 2: 17-1
17 - 1 = 16
Problem 3: 19-1
19 - 1 = 18
Problem 4: 14-1
14 - 1 = 13
Step 1: For 12 - 1

Take away 1 from 12, which gives you the number before 12: 11

Step 2: For 17 - 1

Take away 1 from 17, which gives you the number before 17: 16

Step 3: For 19 - 1

Take away 1 from 19, which gives you the number before 19: 18

Step 4: For 14 - 1

Take away 1 from 14, which gives you the number before 14: 13

12 - 1 = 11, 17 - 1 = 16, 19 - 1 = 18, 14 - 1 = 13
Final answers:

12 - 1 = 11, 17 - 1 = 16, 19 - 1 = 18, 14 - 1 = 13

Applied rules:

• Minus one rule: Any number minus 1 equals the previous number

• Pattern recognition: n - 1 = the number before n in counting

• Counting connection: This connects to counting backwards

• Practice Tip: Think of the number that comes just before in counting

3 Minus Two Facts
Fact Family 3
Practice minus two facts: 13 - 2 = ?, 16 - 2 = ?, 18 - 2 = ?, 15 - 2 = ?
Difficulty: Beginner Time: ~2 minutes Skills: Basic Subtraction, Counting Back, Number Sense
Definition:

Minus two facts: Subtraction facts where the subtrahend is 2. The answer is always two less than the minuend.

Note: When you subtract 2 from any number, you get the number that comes two places before it in counting order.

Step-by-step fact learning:
  1. Recognize that you're subtracting two
  2. Count back two from the minuend
  3. The answer is two numbers before in counting order
  4. Memorize this pattern: n - 2 = (n-2)
Problem 1: 13-2
13 - 2 = 11
Problem 2: 16-2
16 - 2 = 14
Problem 3: 18-2
18 - 2 = 16
Problem 4: 15-2
15 - 2 = 13
Step 1: For 13 - 2

Take away 2 from 13, which gives you two numbers before 13: 12, 11

Step 2: For 16 - 2

Take away 2 from 16, which gives you two numbers before 16: 15, 14

Step 3: For 18 - 2

Take away 2 from 18, which gives you two numbers before 18: 17, 16

Step 4: For 15 - 2

Take away 2 from 15, which gives you two numbers before 15: 14, 13

13 - 2 = 11, 16 - 2 = 14, 18 - 2 = 16, 15 - 2 = 13
Final answers:

13 - 2 = 11, 16 - 2 = 14, 18 - 2 = 16, 15 - 2 = 13

Applied rules:

• Minus two rule: Any number minus 2 equals the number two places before

• Pattern recognition: n - 2 = the number that is two less than n

• Counting connection: This connects to counting backwards by two

• Practice Tip: Count back two numbers from the starting number

4 Minus Three Facts
Fact Family 4
Practice minus three facts: 14 - 3 = ?, 17 - 3 = ?, 19 - 3 = ?, 16 - 3 = ?
Difficulty: Beginner Time: ~3 minutes Skills: Basic Subtraction, Counting Back, Number Sense
Definition:

Minus three facts: Subtraction facts where the subtrahend is 3. The answer is always three less than the minuend.

Note: When you subtract 3 from any number, you get the number that comes three places before it in counting order.

Step-by-step fact learning:
  1. Recognize that you're subtracting three
  2. Count back three from the minuend
  3. The answer is three numbers before in counting order
  4. Memorize this pattern: n - 3 = (n-3)
Problem 1: 14-3
14 - 3 = 11
Problem 2: 17-3
17 - 3 = 14
Problem 3: 19-3
19 - 3 = 16
Problem 4: 16-3
16 - 3 = 13
Step 1: For 14 - 3

Take away 3 from 14, which gives you three numbers before 14: 13, 12, 11

Step 2: For 17 - 3

Take away 3 from 17, which gives you three numbers before 17: 16, 15, 14

Step 3: For 19 - 3

Take away 3 from 19, which gives you three numbers before 19: 18, 17, 16

Step 4: For 16 - 3

Take away 3 from 16, which gives you three numbers before 16: 15, 14, 13

14 - 3 = 11, 17 - 3 = 14, 19 - 3 = 16, 16 - 3 = 13
Final answers:

14 - 3 = 11, 17 - 3 = 14, 19 - 3 = 16, 16 - 3 = 13

Applied rules:

• Minus three rule: Any number minus 3 equals the number three places before

• Pattern recognition: n - 3 = the number that is three less than n

• Counting connection: This connects to counting backwards by three

• Practice Tip: Count back three numbers from the starting number

5 Minus Four Facts
Fact Family 5
Practice minus four facts: 15 - 4 = ?, 18 - 4 = ?, 20 - 4 = ?, 17 - 4 = ?
Difficulty: Intermediate Time: ~3 minutes Skills: Basic Subtraction, Counting Back, Number Sense
Definition:

Minus four facts: Subtraction facts where the subtrahend is 4. The answer is always four less than the minuend.

Note: When you subtract 4 from any number, you get the number that comes four places before it in counting order.

Step-by-step fact learning:
  1. Recognize that you're subtracting four
  2. Count back four from the minuend
  3. The answer is four numbers before in counting order
  4. Memorize this pattern: n - 4 = (n-4)
Problem 1: 15-4
15 - 4 = 11
Problem 2: 18-4
18 - 4 = 14
Problem 3: 20-4
20 - 4 = 16
Problem 4: 17-4
17 - 4 = 13
Step 1: For 15 - 4

Take away 4 from 15, which gives you four numbers before 15: 14, 13, 12, 11

Step 2: For 18 - 4

Take away 4 from 18, which gives you four numbers before 18: 17, 16, 15, 14

Step 3: For 20 - 4

Take away 4 from 20, which gives you four numbers before 20: 19, 18, 17, 16

Step 4: For 17 - 4

Take away 4 from 17, which gives you four numbers before 17: 16, 15, 14, 13

15 - 4 = 11, 18 - 4 = 14, 20 - 4 = 16, 17 - 4 = 13
Final answers:

15 - 4 = 11, 18 - 4 = 14, 20 - 4 = 16, 17 - 4 = 13

Applied rules:

• Minus four rule: Any number minus 4 equals the number four places before

• Pattern recognition: n - 4 = the number that is four less than n

• Counting connection: This connects to counting backwards by four

• Practice Tip: Count back four numbers from the starting number

Subtraction Facts 6-10 with Solutions
6 Minus Five Facts
Fact Family 6
Practice minus five facts: 16 - 5 = ?, 19 - 5 = ?, 20 - 5 = ?, 18 - 5 = ?
Definition:

Minus five facts: Subtraction facts where the subtrahend is 5. The answer is always five less than the minuend.

Note: When you subtract 5 from any number, you get the number that comes five places before it in counting order.

Step-by-step fact learning:
  1. Recognize that you're subtracting five
  2. Count back five from the minuend
  3. The answer is five numbers before in counting order
  4. Memorize this pattern: n - 5 = (n-5)
Problem 1: 16-5
16 - 5 = 11
Problem 2: 19-5
19 - 5 = 14
Problem 3: 20-5
20 - 5 = 15
Problem 4: 18-5
18 - 5 = 13
Step 1: For 16 - 5

Take away 5 from 16, which gives you five numbers before 16: 15, 14, 13, 12, 11

Step 2: For 19 - 5

Take away 5 from 19, which gives you five numbers before 19: 18, 17, 16, 15, 14

Step 3: For 20 - 5

Take away 5 from 20, which gives you five numbers before 20: 19, 18, 17, 16, 15

Step 4: For 18 - 5

Take away 5 from 18, which gives you five numbers before 18: 17, 16, 15, 14, 13

16 - 5 = 11, 19 - 5 = 14, 20 - 5 = 15, 18 - 5 = 13
Final answers:

16 - 5 = 11, 19 - 5 = 14, 20 - 5 = 15, 18 - 5 = 13

7 Minus Six Facts
Fact Family 7
Practice minus six facts: 17 - 6 = ?, 20 - 6 = ?, 19 - 6 = ?, 18 - 6 = ?
Definition:

Minus six facts: Subtraction facts where the subtrahend is 6. The answer is always six less than the minuend.

Note: When you subtract 6 from any number, you get the number that comes six places before it in counting order.

Step-by-step fact learning:
  1. Recognize that you're subtracting six
  2. Count back six from the minuend
  3. The answer is six numbers before in counting order
  4. Memorize this pattern: n - 6 = (n-6)
Problem 1: 17-6
17 - 6 = 11
Problem 2: 20-6
20 - 6 = 14
Problem 3: 19-6
19 - 6 = 13
Problem 4: 18-6
18 - 6 = 12
Step 1: For 17 - 6

Take away 6 from 17, which gives you six numbers before 17: 16, 15, 14, 13, 12, 11

Step 2: For 20 - 6

Take away 6 from 20, which gives you six numbers before 20: 19, 18, 17, 16, 15, 14

Step 3: For 19 - 6

Take away 6 from 19, which gives you six numbers before 19: 18, 17, 16, 15, 14, 13

Step 4: For 18 - 6

Take away 6 from 18, which gives you six numbers before 18: 17, 16, 15, 14, 13, 12

17 - 6 = 11, 20 - 6 = 14, 19 - 6 = 13, 18 - 6 = 12
Final answers:

17 - 6 = 11, 20 - 6 = 14, 19 - 6 = 13, 18 - 6 = 12

8 Minus Seven Facts
Fact Family 8
Practice minus seven facts: 18 - 7 = ?, 20 - 7 = ?, 19 - 7 = ?
Definition:

Minus seven facts: Subtraction facts where the subtrahend is 7. The answer is always seven less than the minuend.

Note: When you subtract 7 from any number, you get the number that comes seven places before it in counting order.

Step-by-step fact learning:
  1. Recognize that you're subtracting seven
  2. Count back seven from the minuend
  3. The answer is seven numbers before in counting order
  4. Memorize this pattern: n - 7 = (n-7)
Problem 1: 18-7
18 - 7 = 11
Problem 2: 20-7
20 - 7 = 13
Problem 3: 19-7
19 - 7 = 12
Step 1: For 18 - 7

Take away 7 from 18, which gives you seven numbers before 18: 17, 16, 15, 14, 13, 12, 11

Step 2: For 20 - 7

Take away 7 from 20, which gives you seven numbers before 20: 19, 18, 17, 16, 15, 14, 13

Step 3: For 19 - 7

Take away 7 from 19, which gives you seven numbers before 19: 18, 17, 16, 15, 14, 13, 12

18 - 7 = 11, 20 - 7 = 13, 19 - 7 = 12
Final answers:

18 - 7 = 11, 20 - 7 = 13, 19 - 7 = 12

9 Minus Eight Facts
Fact Family 9
Practice minus eight facts: 19 - 8 = ?, 20 - 8 = ?
Definition:

Minus eight facts: Subtraction facts where the subtrahend is 8. The answer is always eight less than the minuend.

Note: When you subtract 8 from any number, you get the number that comes eight places before it in counting order.

Step-by-step fact learning:
  1. Recognize that you're subtracting eight
  2. Count back eight from the minuend
  3. The answer is eight numbers before in counting order
  4. Memorize this pattern: n - 8 = (n-8)
Problem 1: 19-8
19 - 8 = 11
Problem 2: 20-8
20 - 8 = 12
Step 1: For 19 - 8

Take away 8 from 19, which gives you eight numbers before 19: 18, 17, 16, 15, 14, 13, 12, 11

Step 2: For 20 - 8

Take away 8 from 20, which gives you eight numbers before 20: 19, 18, 17, 16, 15, 14, 13, 12

19 - 8 = 11, 20 - 8 = 12
Final answers:

19 - 8 = 11, 20 - 8 = 12

10 Minus Nine and Ten Facts
Fact Family 10
Practice minus nine and ten facts: 20 - 9 = ?, 20 - 10 = ?, 19 - 10 = ?, 18 - 9 = ?
Definition:

Minus nine and ten facts: Subtraction facts where the subtrahend is 9 or 10. The answer is always the difference between the numbers.

Note: When the minuend and subtrahend are the same, the answer is always 0. When the subtrahend is one less than the minuend, the answer is 1.

Step-by-step fact learning:
  1. Recognize when the numbers are the same (answer is 0)
  2. Recognize when the subtrahend is one less than the minuend (answer is 1)
  3. Count back the appropriate number of steps
  4. Memorize these patterns
Problem 1: 20-9
20 - 9 = 11
Problem 2: 20-10
20 - 10 = 10
Problem 3: 19-10
19 - 10 = 9
Problem 4: 18-9
18 - 9 = 9
Step 1: For 20 - 9

Take away 9 from 20, which gives you nine numbers before 20: 19, 18, 17, 16, 15, 14, 13, 12, 11

Step 2: For 20 - 10

Take away 10 from 20, which gives you ten numbers before 20: 19, 18, 17, 16, 15, 14, 13, 12, 11, 10

Step 3: For 19 - 10

Take away 10 from 19, which gives you ten numbers before 19: 18, 17, 16, 15, 14, 13, 12, 11, 10, 9

Step 4: For 18 - 9

Take away 9 from 18, which gives you nine numbers before 18: 17, 16, 15, 14, 13, 12, 11, 10, 9

20 - 9 = 11, 20 - 10 = 10, 19 - 10 = 9, 18 - 9 = 9
Final answers:

20 - 9 = 11, 20 - 10 = 10, 19 - 10 = 9, 18 - 9 = 9

Detailed Summary: Subtraction Facts 0-20
Core Concepts and Definitions:

Subtraction Facts: Basic subtraction problems where the minuend is between 0 and 20, and the subtrahend is between 0 and the minuend.

Minuend: The number from which another number is subtracted in a subtraction problem.

Subtrahend: The number that is subtracted from another number in a subtraction problem.

Difference: The result of a subtraction problem.

Number Sense: Understanding the relationships between numbers and their quantities.

Mathematical Fluency: The ability to perform calculations quickly and accurately.

Counting Back: The strategy of starting with the minuend and counting backwards by the subtrahend.

Core Rules and Principles:
  1. Zero Property: Any number minus 0 equals the original number (n - 0 = n).
  2. Identity Property: Any number minus itself equals 0 (n - n = 0).
  3. Counting Back: Subtracting by counting backwards from the minuend.
  4. Sequential Pattern: Each subtraction fact follows a predictable pattern.
  5. Verification: Always check by adding the difference to the subtrahend.
Step-by-Step Procedures: 1) Identify minuend and subtrahend, 2) Choose the appropriate counting strategy, 3) Apply the strategy systematically, 4) Identify the difference, 5) Verify the result.
Examples (Simple → Advanced): Simple: 10 - 0 = 10 (zero property), Advanced: 20 - 9 = 11 (counting back). Facts progress from basic properties to more complex calculations.
Tips: Practice regularly, start with smaller numbers, use fingers or objects to visualize, memorize patterns, verify answers by adding back.
Common Pitfalls: Confusing minuend and subtrahend, counting incorrectly, forgetting to verify answers, not memorizing basic facts.

Key Takeaways for Memorization

  • n - 0 = n (any number minus zero equals itself)
  • n - n = 0 (any number minus itself equals zero)
  • n - 1 = the number before n in counting
  • n - 2 = two numbers before n in counting
  • Subtracting larger numbers requires counting back more steps
  • Practice regularly to build automaticity
  • Always verify by adding the difference back to the subtrahend
  • Look for patterns in subtraction facts
Essential Teaching Points:

• Pattern Recognition: Help students identify patterns in subtraction facts

• Concrete to Abstract: Begin with physical objects, progress to visual representations, then mental math

• Consistent Practice: Regular exposure builds automaticity and fluency

• Verification Skills: Teach students to check their work by using the opposite operation

Subtraction Facts 0-20

Learning Objectives

  • Master subtraction facts 0-20
  • Build number sense within 20
  • Improve mathematical fluency
  • Develop memorization skills
  • Recognize subtraction patterns
  • Apply facts to larger problems
  • Develop verification skills

Minus Zero

n - 0 = n (any number minus zero equals itself)

Same Numbers

n - n = 0 (any number minus itself equals zero)

Count Back From Minuend
Memorize Patterns
Verify by Adding
Practice Regularly
Minuend Subtrahend Difference Rule
n 0 n Zero Property
n 1 n-1 Count Back 1
n 2 n-2 Count Back 2
n n 0 Identity Property

Subtraction Facts Practice Elements

These facts provide the foundation for all future subtraction, building computational fluency and number sense.

Subtraction Facts Success Steps:

1
Identify the minuend and subtrahend in the problem
2
Recognize the pattern or rule that applies
3
Apply the appropriate counting strategy
4
Calculate the difference
5
Verify by adding the difference to the subtrahend
Key Rules, Methods, and Strategies
Zero Property: n - 0 = n
Zero Property
Identity Property: n - n = 0
Identity Property
Key definitions:

Subtraction facts: Basic subtraction problems with minuends from 0 to 20.

Number sense: Understanding the relationship between numbers and their quantities.

Memorization: Learning facts through repetition and pattern recognition.

Complete methodology:
  1. Identify the problem: Recognize the minuend and subtrahend
  2. Apply the appropriate rule: Use zero property, identity property, or counting back
  3. Calculate the result: Perform the subtraction mentally
  4. Verify the result: Check by using the opposite operation
Tip 1: Practice zero facts first (n - 0 = n) as they're the easiest.
Tip 2: Learn identity facts (n - n = 0) early as they're also straightforward.
Tip 3: Use your fingers or draw dots to help visualize the subtraction process.

Tip 4: Check your answer by adding the difference back to the subtrahend to get the minuend.
Common errors: Confusing minuend and subtrahend, counting incorrectly, forgetting to verify answers, not memorizing basic facts.
Success strategies: Practice regularly, use visualization, memorize patterns, verify answers by checking.
Rules to remember:

• Zero property: Any number minus 0 equals itself

• Identity property: Any number minus itself equals 0

• Counting back: Subtract by counting backwards from the minuend

• Verify results: Always check by adding difference to subtrahend

• Memorize patterns: Learn the systematic relationships between numbers

Questions & Answers

Question: I'm learning subtraction facts but sometimes I get confused about which number to start with. How can I remember?

Answer: Great question! Remember these key points:

  • The minuend is the first number in the subtraction problem
  • This is the number you start with
  • The subtrahend is the second number
  • This is the number you take away
  • For example: In 15 - 3, start with 15 and take away 3

Think of it like having 15 cookies and eating 3 of them!

Question: My child is struggling with memorizing subtraction facts. How can I help them build fluency?

Answer: Here are strategies to help your child with subtraction facts:

  • Start with smaller numbers and gradually increase difficulty
  • Use visual aids like counters, number lines, or fingers
  • Practice for short periods regularly rather than long sessions
  • Use games and activities to make practice fun
  • Celebrate small improvements and progress

Remember, building fact fluency takes time and consistent practice!

Question: Why do I need to memorize subtraction facts? Can't I just count on my fingers?

Answer: Memorizing subtraction facts is important because:

  • It makes you faster at solving problems
  • It builds your number sense and understanding
  • It prepares you for harder math problems
  • It's useful when you don't have fingers available
  • It builds confidence in your math abilities

Counting is good to start with, but memorizing facts makes you stronger at math!

Math Glossary

Subtraction Facts
Basic subtraction problems where the minuend is between 0 and 20, and the subtrahend is between 0 and the minuend.
Minuend
The number from which another number is subtracted in a subtraction problem.
Subtrahend
The number that is subtracted from another number in a subtraction problem.
Difference
The result of a subtraction problem.
Zero Property
Any number minus 0 equals the original number (n - 0 = n).
Identity Property
Any number minus itself equals 0 (n - n = 0).
Counting Back
A strategy for subtraction where you start with the minuend and count backwards by the subtrahend.
Mathematical Fluency
The ability to perform calculations quickly and accurately.
Number Sense
Understanding the relationships between numbers and their quantities.
Verification
Checking your answer using the opposite operation to ensure accuracy.

Elementary Subtraction Educational Team

Certified Elementary Mathematics Educators

Our team specializes in developing foundational subtraction skills that build computational fluency and number sense. All content is aligned with Common Core State Standards and designed to promote mathematical understanding through systematic fact practice that prepares students for advanced mathematics.