Ways to Make 20 Addition for Grade 1 Students

Complete guide to understanding different ways to make 20 through addition with visual models, step-by-step exercises, and interactive learning tools.

Ways to Make 20 Solutions: Exercises 1 to 3
1 Make 20 with 10
Exercise 1
Find the number that makes 20 when added to 10: 10 + ___ = 20
Definition:

Ways to make 20: Addition pairs that combine to equal 20. These build on knowledge of ways to make 10.

10
First 10
+
10
Second 10
=
20
Total
10
10
10
10
10
10
10
10
10
10
10 objects
+
10
10
10
10
10
10
10
10
10
10
10 more objects
=
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
Total: 20
Step 1: Start with 10

We have 10 objects

Step 2: Need to reach 20

Count from 10 to 20: 11, 12, 13, 14, 15, 16, 17, 18, 19, 20

Step 3: Count the difference

From 10 to 20 is 10 more

Step 4: Verify the answer

10 + 10 = 20 ✓

10 + 10 = 20
Final answer:

10 + 10 = 20

Applied rules:

• Double fact: 10 + 10 is a double fact equal to 20

• Missing addend: Find what number completes the equation

• Counting strategy: Count from known number to target

2 Make 20 with 11
Exercise 2
Find the number that makes 20 when added to 11: 11 + ___ = 20
Definition:

Complementary pairs to 20: Number pairs that add up to 20 (11+9, 12+8, 13+7, etc.).

1
2
3
4
5
6
7
8
9
10
11
Step 1: Start with 11

We have 11 objects in the twenty frame

Step 2: Count empty spaces

There are 9 empty spaces in the twenty frame

Step 3: Find the missing number

11 + 9 = 20

Step 4: Verify the answer

11 + 9 = 20 ✓

11 + 9 = 20
Final answer:

11 + 9 = 20

Applied rules:

• Twenty frame strategy: Visual tool for making 20

• Part-whole relationship: Parts combine to make the whole

• Missing addend: Find what number completes the equation

3 Make 20 with 12
Exercise 3
Find the number that makes 20 when added to 12: 12 + ___ = 20
Definition:

Decomposition: Breaking apart numbers to understand their relationship to 20.

12
12
12
12
12
12
12
12
12
12
12
12
12 objects
+
8
8
8
8
8
8
8
8
8 more objects
=
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
Total: 20
Step 1: Start with 12

We have 12 objects

Step 2: Need to reach 20

Count from 12 to 20: 13, 14, 15, 16, 17, 18, 19, 20

Step 3: Count the difference

From 12 to 20 is 8 more

Step 4: Verify the answer

12 + 8 = 20 ✓

12 + 8 = 20
Final answer:

12 + 8 = 20

Applied rules:

• Counting strategy: Count from known number to target

• Part-whole relationship: Parts combine to make the whole

• Complementary pairs: 12 and 8 are complements to 20

Ways to Make 20 Solutions: Exercises 4 to 5
4 Make 20 with 13
Exercise 4
Find the number that makes 20 when added to 13: 13 + ___ = 20
Definition:

Base-10 relationship: Understanding how numbers relate to multiples of 10 to make 20.

1
2
3
4
5
6
7
8
9
10
11
12
13
Step 1: Start with 13

We have 13 objects in the twenty frame

Step 2: Count empty spaces

There are 7 empty spaces in the twenty frame

Step 3: Find the missing number

13 + 7 = 20

Step 4: Verify the answer

13 + 7 = 20 ✓

13 + 7 = 20
Final answer:

13 + 7 = 20

Applied rules:

• Twenty frame strategy: Visual tool for making 20

• Complementary pairs: Numbers that add up to 20

• Missing addend: Find what number completes the equation

5 Make 20 with 15
Exercise 5
Find the number that makes 20 when added to 15: 15 + ___ = 20
Definition:

Halfway point: 15 is halfway to 20, so we need 5 more to reach 20.

15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15 objects
+
5
5
5
5
5
5 more objects
=
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
Total: 20
Step 1: Start with 15

We have 15 objects

Step 2: Need to reach 20

Count from 15 to 20: 16, 17, 18, 19, 20

Step 3: Count the difference

From 15 to 20 is 5 more

Step 4: Verify the answer

15 + 5 = 20 ✓

15 + 5 = 20
Final answer:

15 + 5 = 20

Applied rules:

• Counting strategy: Count from known number to target

• Complementary pairs: 15 and 5 are complements to 20

• Base-10 relationship: 15 is 5 less than 20

Ways to Make 20 Addition Concepts
+
Complementary Pairs
To 20
20
Benchmark Number
Important
📊
Twenty Frame
Visual Tool
🎯
Mental Math
Foundation
10 + 10
= 20
11 + 9
= 20
12 + 8
= 20
13 + 7
= 20
14 + 6
= 20
15 + 5
= 20
16 + 4
= 20
17 + 3
= 20
18 + 2
= 20
19 + 1
= 20
a + (20 - a) = 20
Complement Formula
Pair 1
10 + 10
Double fact
Pair 2
11 + 9
Complements to 20
Pair 3
15 + 5
Halfway point
Key Concept: Knowing ways to make 20 helps with mental math.
Memory Aid: "Make 20" strategy for adding larger numbers.
Comprehensive Ways to Make 20 Summary
Key Concepts & Definitions
  • Ways to Make 20
    Addition pairs that combine to equal 20 (10+10, 11+9, 12+8, 13+7, 14+6, 15+5, 16+4, 17+3, 18+2, 19+1)
  • Complementary Pairs
    Number pairs that add up to 20 (e.g., 13 and 7 are complements of 20)
  • Twenty Frame
    A visual tool with 20 spaces used to organize and represent numbers up to 20
  • Benchmark Number
    An important reference number (like 20) that helps with calculations
  • Double Fact
    A number added to itself (e.g., 10 + 10 = 20)
Core Rules & Principles
Complement Rule: a + (20 - a) = 20
Any number plus its complement equals 20
Example: 13 + (20 - 13) = 13 + 7 = 20
Commutative Property: a + b = b + a
The order of numbers doesn't change the sum
Example: 14 + 6 = 6 + 14 = 20
Double Fact: 10 + 10 = 20
Half of 20 is 10, so 10 + 10 makes 20
Example: 10 + 10 = 20
Step-by-Step Methods
Method 1: Counting Strategy
1. Start with the known number
2. Count up to 20
3. The number of counts is the missing addend
Method 2: Twenty Frame Strategy
1. Place objects in the twenty frame
2. Count the empty spaces
3. The empty spaces represent the missing addend
Method 3: Using Known Facts
1. Recall known combinations that make 20
2. Apply the complement principle
3. Verify the answer
Examples (Simple → Advanced)
Simple: 10 + 10 = 20
Adding 10 to 10 gives 20
Moderate: 13 + 7 = 20
Using counting or twenty frame strategy
Advanced: 16 + 4 = 20
Using commutative property: 16 + 4 = 4 + 16 = 20
Complex: 18 + 2 = 20
Recognizing complement pairs automatically
Tips, Tricks & Common Pitfalls
Tip 1: Use twenty frames to visualize making 20.
Tip 2: Remember that 10 + 10 = 20 is a double fact.
Pitfall 1: Forgetting that order doesn't matter in addition.
Pitfall 2: Not recognizing complement pairs automatically.
Key Notes for Memorization
  • Memory Phrase
    "Pairs that make 20: 10 and 10, 11 and 9, 12 and 8, 13 and 7, 14 and 6, 15 and 5."
  • Visual Strategy
    Use twenty frames to see the relationships between numbers.
  • Practice Pattern
    Start with easier pairs (10+10, 11+9) and work toward harder ones.
  • Check Method
    Always verify your answer by adding the two numbers together.

Questions & Answers

Question: How does understanding ways to make 20 build on knowledge of ways to make 10?

Answer: Understanding ways to make 20 builds on ways to make 10 by:

  • Extending patterns: If 3 + 7 = 10, then 13 + 7 = 20
  • Using doubles: If 5 + 5 = 10, then 10 + 10 = 20
  • Building number sense: Understanding that 20 is two tens
  • Developing strategies: Using known facts to solve new problems
  • Creating mental models: Extending visual representations to larger numbers

This creates a strong foundation for addition with larger numbers.

Question: What are effective ways to practice making 20 at home?

Answer: Effective home practice methods include:

  • Twenty frames: Use printable frames with counters or coins
  • Real objects: Use fingers, toys, or snacks to create combinations
  • Games: "Make 20" card games or dice games
  • Counting songs: Chants that emphasize number pairs
  • Technology: Interactive apps that reinforce the concept

Practice for 10-15 minutes daily for optimal learning without fatigue.

Question: How can knowing ways to make 20 help with adding larger numbers?

Answer: Knowing ways to make 20 helps with larger numbers through:

  • Decomposing: Breaking apart numbers to make 20 first
  • Compensation: Adjusting numbers to make friendly 20s
  • Regrouping: Understanding when to carry in addition
  • Mental math: Creating benchmarks for estimation
  • Subtraction: Using 20 to subtract across zeros

This builds a strong foundation for multi-digit arithmetic.