Subtraction with 20 Worksheet - Practice Exercises

Complete subtraction with 20 worksheet: basic facts, place value, and fact families through these 3 comprehensive exercises.

Worksheet Solutions: Exercises 1 to 3
1 Basic Subtraction with 20
Worksheet Problem 1
Complete: 20 - 1 = ?, 20 - 2 = ?, 20 - 3 = ?, 20 - 4 = ?, 20 - 5 = ?, 20 - 6 = ?, 20 - 7 = ?, 20 - 8 = ?, 20 - 9 = ?, 20 - 10 = ?
Definition:

Subtraction with 20: Taking away from 20, which extends place value understanding beyond 10.

Solution methods:
  1. Counting back: Start at 20, count backward by the number being subtracted
  2. Using two ten frames: Fill 20 spaces and remove the specified number
  3. Think addition: What number added to the subtrahend equals 20?
Problem Set
20-n patterns
Answers
19,18,17,16,15,14,13,12,11,10
Step 1: 20 - 1 = 19

Count back: 20→19 (1 step) = 19

Step 2: 20 - 2 = 18

Think addition: What + 2 = 20? Answer: 18

Step 3: 20 - 3 = 17

Pattern: As subtrahend increases by 1, difference decreases by 1

Step 4: Continue pattern

20-4=16, 20-5=15, 20-6=14, 20-7=13, 20-8=12, 20-9=11, 20-10=10

20-1=19, 20-2=18, 20-3=17, 20-4=16, 20-5=15, 20-6=14, 20-7=13, 20-8=12, 20-9=11, 20-10=10
Final answers:

20-1=19, 20-2=18, 20-3=17, 20-4=16, 20-5=15, 20-6=14, 20-7=13, 20-8=12, 20-9=11, 20-10=10

Applied rules:

• Subtraction with 20: Extends place value understanding beyond 10

• Verification: Add answer to subtrahend to check (19 + 1 = 20)

• Patterns: Notice that 20 - n and n + ? = 20 are related

2 Place Value Subtraction
Worksheet Problem 2
Solve: 21 - 20 = ?, 22 - 20 = ?, 23 - 20 = ?, 24 - 20 = ?, 25 - 20 = ?, 26 - 20 = ?, 27 - 20 = ?, 28 - 20 = ?, 29 - 20 = ?, 30 - 20 = ?
Definition:

Place value subtraction: Subtracting 20 from numbers in the twenties and thirties, focusing on the tens place.

Problem Set
n - 20 patterns
Answers
1,2,3,4,5,6,7,8,9,10
Step 1: 21 - 20 = 1

21 has 2 tens and 1 one. Remove 2 tens: 21 - 20 = 1

Step 2: 22 - 20 = 2

22 has 2 tens and 2 ones. Remove 2 tens: 22 - 20 = 2

Step 3: 23 - 20 = 3

Pattern: The answer is always the ones digit of the original number

Step 4: Continue pattern

24-20=4, 25-20=5, 26-20=6, 27-20=7, 28-20=8, 29-20=9, 30-20=10

21-20=1, 22-20=2, 23-20=3, 24-20=4, 25-20=5, 26-20=6, 27-20=7, 28-20=8, 29-20=9, 30-20=10
Final answers:

21-20=1, 22-20=2, 23-20=3, 24-20=4, 25-20=5, 26-20=6, 27-20=7, 28-20=8, 29-20=9, 30-20=10

Applied rules:

• Place value: Removing 20 leaves only the ones digit

• Pattern: The answer is always the ones digit of the original number

• Verification: Add 20 back to check (1 + 20 = 21)

3 Fact Family Worksheet
Worksheet Problem 3
Complete the fact families: 20 - 14 = ?, ? + 14 = 20, 14 + ? = 20, ? - 14 = 6, 20 - 6 = ?, ? + 6 = 20, 6 + ? = 20, ? - 6 = 14
Definition:

Fact family: Related addition and subtraction facts using the same three numbers.

Fact Family
6, 14, 20
Complete Set
20-14=6, 14+6=20, 6+14=20, 20-6=14
Step 1: 20 - 14 = 6

What's left when 14 is taken from 20? Answer: 6

Step 2: 6 + 14 = 20

What number added to 14 makes 20? Answer: 6

Step 3: 14 + 6 = 20

Commutative property: 6 + 14 = 14 + 6 = 20

Step 4: 20 - 6 = 14

What's left when 6 is taken from 20? Answer: 14

20-14=6, 6+14=20, 14+6=20, 20-6=14
Final answers:

20-14=6, 6+14=20, 14+6=20, 20-6=14

Applied rules:

• Fact families: Addition and subtraction are inverse operations

• Relationship: If a + b = c, then c - a = b and c - b = a

• Verification: All four facts in the family are related

📚 SUBTRACTION WITH 20 WORKSHEET - COMPLETE SUMMARY

Definitions:

  • Subtraction with 20: Taking away from 20 or subtracting 20 from larger numbers
  • Place Value: Understanding that numbers have tens and ones places
  • Fact Family: A group of related addition and subtraction facts using the same numbers
  • Worksheet Practice: Structured exercises for skill reinforcement
  • Number Bonds: Pairs of numbers that combine to make a specific total

Core Rules & Principles:

  • Subtracting from 20: The answer is always what's needed to make 20
  • Subtracting 20: The answer is always the ones digit of the original number
  • Verification: Always check by adding the answer back to the subtracted amount
  • Fact Families: Addition and subtraction are inverse operations

Step-by-Step Methods:

  1. For 20 - n: Count back n steps from 20, or think "What + n = 20?"
  2. For n - 20: Focus on the ones place of the original number
  3. For fact families: Identify the three numbers and create four related facts
  4. Verify: Always add the difference to the subtracted number to check

Examples (Simple to Advanced):

  • Basic: 20 - 5 = 15
  • Place Value: 24 - 20 = 4
  • Fact Family: 20 - 14 = 6, 14 + 6 = 20, 6 + 14 = 20, 20 - 6 = 14
  • Application: "I have 20 stickers and give away 8. How many left?" → 20 - 8 = 12

Tips & Tricks:

  • Use Two Ten Frames: Visualize the numbers to understand the relationship
  • Think Addition: For 20 - 14, ask "What + 14 = 20?"
  • Pattern Recognition: When subtracting 20, the ones digit stays the same
  • Practice Bonds: Know all pairs that make 20 (1+19, 2+18, 3+17, etc.)

Common Pitfalls:

  • Confusing 20 - n with n - 20
  • Forgetting that subtracting 20 changes only the tens place
  • Not recognizing the relationship between addition and subtraction
  • Making calculation errors with larger numbers

Key Notes for Memorization:

  • Practice the pairs that make 20: 1+19, 2+18, 3+17, 4+16, 5+15, 6+14, 7+13, 8+12, 9+11, 10+10
  • When subtracting 20, focus only on the ones digit
  • Addition and subtraction are opposites: one undoes the other
  • Use the 10 strategy: break subtraction into two steps (20 - 17 = 20 - 10 - 7 = 3)
Worksheet Concepts and Patterns
20 - n = (20 - n), n - 20 = ones digit
Subtraction Patterns
Subtracting from 20
20 - 13 = 7 because 13 + 7 = 20
Complement to 20
Subtracting 20
25 - 20 = 5 (ones digit)
Place value concept
Fact Families
14+6=20, 6+14=20, 20-14=6, 20-6=14
Related facts
Key Rule: Subtraction with 20 builds place value understanding.
Verification: Always add the answer back to check.
Worksheet Strategies:
  1. Look for patterns: Notice relationships between problems
  2. Start with easier problems: Build confidence first
  3. Use visual aids: Draw dots or use counters when needed
  4. Check answers: Verify each answer before moving on
Tip 1: Complete the easier problems first to build momentum.
Tip 2: Use your knowledge of 20 to solve harder problems.
Tip 3: Draw pictures to visualize difficult problems.
Tip 4: Always verify by adding your answer back.
Worksheet Practice Grid
20 - 14 = 6, so 6 + 14 = 20
Inverse Relationship
Worksheet Structure:

Number Bonds: Understanding how numbers combine to make 20

Place Value: Recognizing tens and ones positions

Fact Families: Connecting addition and subtraction

20 - 1
= 19
20 - 2
= 18
20 - 3
= 17
20 - 4
= 16
20 - 5
= 15
20 - 6
= 14
20 - 7
= 13
20 - 8
= 12
20 - 9
= 11
20 - 10
= 10
21 - 20
= 1
22 - 20
= 2
23 - 20
= 3
24 - 20
= 4
25 - 20
= 5
26 - 20
= 6
27 - 20
= 7
28 - 20
= 8
29 - 20
= 9
30 - 20
= 10
Common Mistake: Confusing 20 - n with n - 20.
Memory Aid: "What goes with 14 to make 20?" for 20 - 14.
Practice Strategy: Start with manipulatives, then move to abstract.
Verification: Always add difference to subtracted amount to check.
Subtraction Properties: Order matters, zero property (n-0=n), n-n=0.
Place Value Skills: Foundation for larger number operations.
Essential Worksheet Facts:

• Subtraction with 20 builds foundational place value understanding

• The pairs that make 20 should be memorized: (1,19), (2,18), (3,17), (4,16), (5,15), (6,14), (7,13), (8,12), (9,11), (10,10)

• When subtracting 20 from twenty-something numbers, the answer is the ones digit

• Always verify your answer by adding the difference back to the subtracted amount

Worksheet Extensions and Challenges
20 - n and n + ? = 20 are related
Inverse Operations
Extended concepts:

Decomposition: Breaking numbers into parts to make subtraction easier

Compensation: Adjusting numbers to make subtraction simpler

Regrouping: Preparing for subtraction with borrowing

Advanced worksheet methodology:
  1. Connect to 30: Extend patterns to subtraction within 30
  2. Use number lines: Visualize jumps of 20
  3. Group strategies: Organize numbers for easier computation
  4. Verify with multiple methods: Cross-check answers
Tip 1: Once you know 20 - 6 = 14, you know 26 - 20 = 6.
Tip 2: Use your knowledge of 20 to solve bigger problems.
Tip 3: Practice with two ten frames to visualize the relationships.
Tip 4: Connect subtraction with 20 to addition facts.
Common errors: Confusing direction of subtraction, place value misunderstandings.
Success strategies: Visual aids, fact families, consistent practice.
Advanced worksheet principles:

• Understanding subtraction with 20 is foundational for multi-digit operations

• Patterns with 20 extend to larger numbers (100s, 1000s)

• The relationship between addition and subtraction is fundamental to algebra

• Verification through inverse operations builds mathematical reasoning

• Place value understanding from 20 subtraction supports number sense

Questions & Answers

Question: My child completes subtraction with 20 worksheets quickly but makes careless errors. How can I help them slow down and be more accurate?

Answer: This is a common issue with confident students! Here are strategies to promote accuracy:

  • Implement a "check your work" rule: have them verify each answer by adding back.
  • Use a slower pace with fewer problems per session.
  • Have them say problems aloud as they solve them.
  • Create a "show your work" requirement, even for simple problems.

Try the "read, solve, check" approach: read the problem, solve it, then check the answer before moving on.

Quality over speed is especially important when building foundational skills.

Question: What's the most effective way to structure subtraction with 20 worksheets for first graders?

Answer: Effective worksheet structure includes:

  • Small sections: 5-10 problems per section to prevent overwhelm
  • Progressive difficulty: Start with basic facts, advance to applications
  • Visual elements: Include ten frames, number lines, or pictures
  • Fact families: Connect addition and subtraction

Example structure: 5 problems of 20 - n, 5 problems of n - 20, 5 fact family problems.

Include space for students to show their work and encourage verification strategies.

Question: How can I differentiate subtraction with 20 worksheets for students at different ability levels?

Answer: Differentiation strategies include:

  • For beginners: Provide two ten frames or manipulatives, fewer problems
  • For proficient students: Include missing number problems or word problems
  • For advanced: Challenge with larger numbers or multi-step problems
  • Choice boards: Let students select from different problem types

Create tiered worksheets with the same core concept but varying complexity.

Allow students to progress at their own pace while providing targeted support.