Solved Exercises on Addition Within 20 in Grade 1

Master addition within 20: basic facts, number bonds, visual representation, and word problems through these 5 detailed exercises.

Solution: Exercises 1 to 3
1 Basic Addition Facts
Exercise 1
Solve: 8 + 5 = ?
Definition:

Addition: Combining two or more numbers to find their total

Basic Facts: Addition problems with numbers from 0 to 20

Within 20: Problems where the sum is 20 or less

Making Ten Method:
  1. Start with the first number (8)
  2. Figure out how many more to make 10 (2 more to make 10)
  3. Take those 2 from the second number (5 - 2 = 3 left)
  4. Add the remaining to 10 (10 + 3 = 13)
Step 1: Start with the first number

Start counting at 8

Step 2: Count forward 5 more numbers

Count: 9, 10, 11, 12, 13

Step 3: Land on the answer

We land on 13

Step 4: Write the equation

8 + 5 = 13

8 + 5 = 13
Final answer:

8 + 5 = 13

Applied rules:

• Counting forward: Adding means moving to larger numbers

• Sequential counting: Count one number at a time

• Final position: The last number reached is the sum

2 Number Bonds
Exercise 2
Show how 12 can be made: 7 + ? = 12
Definition:

Number Bond: Shows how a number can be split into parts

Part-Whole Relationship: Smaller numbers that combine to make a larger number

12
7
5
Step 1: Identify the whole number

We want to make 12 (the whole)

Step 2: Identify one part

One part is 7

Step 3: Find the missing part

Count up from 7 to 12: 7, 8, 9, 10, 11, 12

We counted 5 more numbers, so the missing part is 5

Step 4: Verify the bond

7 + 5 = 12 ✓

7 + 5 = 12
Final answer:

7 + 5 = 12, so the missing number is 5

Applied rules:

• Number bonds: Help understand how numbers break apart

• Counting up: Start with the known part and count to the whole

• Verification: Check that the parts add up to the whole

3 Ten Frame Addition
Exercise 3
Solve: 9 + 6 = ? using ten frames
Definition:

Ten Frame: A visual tool with 10 boxes to show numbers

Visual Learning: Using pictures to understand numbers

1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
Step 1: Show the first number

Fill 9 boxes in the first ten frame

Step 2: Add more to the first frame

Put 1 more in the first frame to make 10

Step 3: Add remaining to second frame

Put the remaining 5 in the second frame

Step 4: Count total

First frame: 10, Second frame: 5, Total: 15

9 + 6 = 15
Final answer:

9 + 6 = 15

Applied rules:

• Ten frame strategy: Making 10 first makes addition easier

• Visual grouping: Seeing numbers in groups of 10

• Sequential counting: Counting by tens and ones

Rules and methods, laws,...
\(8 + 5 = 13\)
Addition Within 20
Commutative
Property
8 + 5 = 5 + 8
Making Ten
Strategy
8 + 5 = 10 + 3
Identity
Property
n + 0 = n
Key definitions:

Addition: Combining two or more quantities to find the total

Sum: The result of an addition problem

Addends: The numbers being added together

Complete methodology:
  1. Identify addends: Recognize the numbers to be added
  2. Choose strategy: Counting, making ten, or mental math
  3. Execute calculation: Perform the addition
  4. Verify answer: Check through reverse counting or alternative method
  5. Record result: Write the complete equation
Tip 1: Use the "making ten" strategy: 8 + 5 = 8 + 2 + 3 = 10 + 3 = 13.
Tip 2: Start with the larger number and count up.
Tip 3: Use ten frames to visualize numbers.
Tip 4: Look for doubles (like 6+6) and near doubles.
Common errors: Miscounting, forgetting to count all addends, starting from wrong number.
Key concepts: Understanding that addition combines quantities, recognizing number patterns.
Rules to remember:

• Commutative: Order doesn't matter (8 + 5 = 5 + 8)

• Making ten: Break numbers to make 10 first (9 + 4 = 9 + 1 + 3 = 13)

• Counting up: Addition means moving to larger numbers

• Verification: Always check your answer

Addition Facts Table (11-20)
6+6=12
6+7=13
6+8=14
6+9=15
6+10=16
7+5=12
7+6=13
7+7=14
7+8=15
7+9=16
8+4=12
8+5=13
8+6=14
8+7=15
8+8=16
9+3=12
9+4=13
9+5=14
9+6=15
9+7=16
10+2=12
10+3=13
10+4=14
10+5=15
10+6=16
Solution: Exercises 4 to 5
4 Word Problems
Exercise 4
Emma has 12 stickers. Her friend gives her 7 more stickers. How many stickers does Emma have now?
Definition:

Word Problem: A math question written in story form

Real-world Application: Connecting math to everyday situations

Step 1: Identify what we know

Emma starts with 12 stickers

Her friend gives her 7 more stickers

Step 2: Identify what we need to find

Total stickers Emma has now

Step 3: Set up the addition

Start with + More = Total

12 + 7 = ?

Step 4: Solve using counting

Count: 12, 13, 14, 15, 16, 17, 18, 19

So 12 + 7 = 19

12 + 7 = 19
Final answer:

Emma has 19 stickers now

Applied rules:

• Story understanding: Find the important numbers

• Keyword identification: "More" means addition

• Problem solving: Convert story to math equation

5 Mixed Addition Problems
Exercise 5
Solve: 14 + 3 = ? and 9 + 8 = ?
Definition:

Mixed Problems: Different addition problems to practice the method

Consistent Application: Using the same strategy for various problems

Step 1: Solve 14 + 3

Start at 14, count 3 more: 15, 16, 17

So 14 + 3 = 17

Step 2: Solve 9 + 8

Use making ten strategy: 9 + 1 = 10, 8 - 1 = 7, so 10 + 7 = 17

So 9 + 8 = 17

Step 3: Notice the pattern

Both problems equal 17, but through different strategies

Step 4: Verify both answers

Count jumps: 14 + 3 has 3 jumps, 9 + 8 uses making ten strategy ✓

14 + 3 = 17
9 + 8 = 17
Final answer:

14 + 3 = 17 and 9 + 8 = 17

Applied rules:

• Flexible strategies: Different problems may need different approaches

• Making ten: Break numbers to make 10 first when helpful

• Verification: Always check your answers

Addition Within 20 - Complete Guide
\(9 + 6 = 15\)
Basic Addition Facts
Key definitions:

Addition: The mathematical operation of combining two or more quantities

Within 20: Addition problems where the sum does not exceed 20

Addends: The numbers being added together in an addition problem

Complete methodology:
  1. Number Recognition: Identify the numbers to be added
  2. Strategy Selection: Choose counting, making ten, or mental math
  3. Sequential Execution: Perform the addition step by step
  4. Result Verification: Check the answer through alternative method
  5. Equation Recording: Write the complete mathematical sentence
Tip 1: Use the "making ten" strategy when possible (9 + 6 = 9 + 1 + 5 = 15).
Tip 2: Practice number bonds to build instant recall.
Tip 3: Use ten frames or objects when visualizing is helpful.
Tip 4: Look for doubles (like 8+8, 9+9) and near doubles.
Visual benefits: Concrete objects and visual aids make abstract concepts understandable.
Memory aids: Repeated practice builds automaticity for future math.
Essential formulas:

• Addition equation: Addend + Addend = Sum

• Commutative property: a + b = b + a

• Identity property: n + 0 = n

• Making ten strategy: a + b = (a + c) + (b - c) where a + c = 10

Addition Within 20 Workflow

📊
Step-by-Step Process
1
See Numbers
2
Choose Strategy
3
Apply Method
4
Verify
5
Write
Addition Patterns

10 + 1 = 11

10 + 2 = 12

10 + 3 = 13

10 + 4 = 14

10 + 5 = 15

Practice Makes Perfect!

Questions & Answers

Question: Why do we learn addition within 20? Isn't that too hard compared to 10?

Answer: Great question! Addition within 20 builds on what you learned with 10. Here's why it's important:

  • Building on basics: You already know addition within 10, now you're extending it
  • Real-world numbers: We often add numbers larger than 10 in daily life
  • Strategy development: You learn helpful tricks like "making ten"
  • Preparation: Sets you up for even larger numbers later

Think of it like climbing stairs - you mastered step 1-10, now you're going up to step 20!

Example: 9 + 6 becomes easier when you think "9 + 1 = 10, and 6 - 1 = 5, so 10 + 5 = 15."

Question: My child sometimes struggles with 8 + 7 and gets confused. What's the best strategy to teach?

Answer: The "making ten" strategy works great for 8 + 7! Here's how:

  • Start with 8: Show 8 objects or draw 8 dots
  • Need 2 more to make 10: Take 2 from the 7 (8 + 2 = 10)
  • Remaining from 7: 7 - 2 = 5 left
  • Final step: 10 + 5 = 15

So: 8 + 7 = 8 + 2 + 5 = 10 + 5 = 15

Practice this strategy with similar problems like 9 + 4, 7 + 6, 8 + 5 to build the pattern.

Visual aids like ten frames help make this concrete!

Question: Sometimes I forget 15 + 3. Do I always have to count from 15?

Answer: At first, counting is perfectly fine! But here are faster ways:

  • Think about tens: 15 is 10 + 5, so 15 + 3 = 10 + 5 + 3 = 10 + 8 = 18
  • Just add to the ones: Keep the 10, add 5 + 3 = 8, so it's 18
  • Count on from 15: Just 16, 17, 18 (only 3 numbers)
  • Practice patterns: 15 + 1 = 16, 15 + 2 = 17, 15 + 3 = 18

Start by counting, but over time you'll remember that 15 + 3 = 18 automatically. It takes practice!

Think of it like learning to ride a bike - you start slowly and get faster with practice.

Question: What are some effective ways to practice addition within 20?

Answer: Effective practice combines repetition with engagement! Here are strategies:

  • Flashcards: Focus on "hard" facts first
  • Ten frames: Visualize numbers and making tens
  • Number line practice: Jump forward to add
  • Word problems: Connect math to real situations

Effective practice strategies:

  • Practice 5-10 minutes daily rather than long sessions
  • Focus on patterns like doubles and near doubles
  • Use games like "Addition War" with playing cards
  • Practice the "making ten" strategy regularly

The key is consistent, focused practice with immediate feedback!