Solved Exercises on Addition Facts with Sum of 10 in Grade 2

Master addition facts with sum of 10: number bonds, counting strategies, and mental math techniques through these 5 detailed exercises.

Solution: Exercises 1 to 3
1 Basic sum of 10
Exercise 1
Find the missing number: 7 + ? = 10
Definition:

Number bond: Two numbers that add up to make a specific total (in this case, 10)

Missing addend: The unknown number that completes the addition equation

Number bond method:
  1. Start with the known number (7)
  2. Count up to the target number (10)
  3. Count how many you counted: 8, 9, 10 (that's 3)
  4. The missing number is 3
Expression
7 + ? = 10
Strategy
Counting up
Answer
3
Step 1: Start with 7

We have 7 objects

Step 2: Count up to 10

How many more do we need to reach 10?

Step 3: Count the difference

From 7 to 10: 8, 9, 10 (that's 3 more)

7 + 3 = 10
Final answer:

7 + 3 = 10

Applied rules:

• Counting up: Start with the smaller number and count up to the larger

• Number bond relationship: 7 and 3 are partners that make 10

• Verification: Always check by adding to confirm the answer

2 Finding complements
Exercise 2
Find the missing number: ? + 4 = 10
Definition:

Complement to 10: The number that, when added to another, equals 10

Missing addend: The unknown number that completes the addition equation

Expression
? + 4 = 10
Complement
6
Verification
6 + 4 = 10
Step 1: Understand the equation

We need to find what number plus 4 equals 10

Step 2: Use subtraction to find the complement

10 - 4 = 6

Step 3: Verify by addition

6 + 4 = 10 ✓

6 + 4 = 10
Final answer:

6 + 4 = 10

Applied rules:

• Subtraction as inverse: To find a missing addend, subtract the known addend from the sum

• Complement pairs: 6 and 4 are complements to 10

• Verification: Always check by adding to confirm the answer

3 Mixed number bonds
Exercise 3
Find the missing number: 2 + ? = 10
Definition:

Number bond to 10: Pairs of numbers that add up to exactly 10

Part-whole relationship: Smaller parts combine to make the whole (10)

Expression
2 + ? = 10
Number bond
2 + 8 = 10
Answer
8
Step 1: Recognize the number bond

We need to find the partner of 2 that makes 10

Step 2: Count up from 2 to 10

3, 4, 5, 6, 7, 8, 9, 10 (that's 8 more)

Step 3: Verify the answer

2 + 8 = 10 ✓

Step 4: Confirm the answer

2 + 8 = 10

2 + 8 = 10
Final answer:

2 + 8 = 10

Applied rules:

• Number bonds to 10: 1+9, 2+8, 3+7, 4+6, 5+5

• Part-whole thinking: Understanding how parts combine to make 10

• Mental math: Knowing number bonds helps solve problems quickly

Addition Facts with Sum of 10 - Core Concepts
a + b = 10
Number Bonds to 10
Bond 1
1 + 9 = 10
One and nine
Bond 2
2 + 8 = 10
Two and eight
Bond 3
3 + 7 = 10
Three and seven
Bond 4
4 + 6 = 10
Four and six
Bond 5
5 + 5 = 10
Five and five
Bond 6
6 + 4 = 10
Six and four
Bond 7
7 + 3 = 10
Seven and three
Bond 8
8 + 2 = 10
Eight and two
Bond 9
9 + 1 = 10
Nine and one
Key definitions:

Addition: Combining two or more numbers to find their total

Sum: The result of adding numbers together

Addend: The numbers being added together

Number bond: A relationship showing how numbers combine to make a total

Complement: The number that, when added to another, equals a specific target (here, 10)

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

Addition strategies:
  1. Counting on: Start with the larger number and count up
  2. Using number bonds: Know pairs that add to 10
  3. Subtraction as inverse: Use subtraction to find missing addends
  4. Commutative property: Change order to make it easier
  5. Visualizing: Picture objects being combined
Tip 1: Practice number bonds to 10 daily for quick recall.
Tip 2: Use fingers or manipulatives to visualize number bonds.
Tip 3: Remember that number bonds work both ways (3+7=10 and 7+3=10).
Tip 4: Always verify by adding to check your answer.
Common errors: Forgetting that order doesn't matter in addition, starting to count from the first number instead of the next number.
Memorization tip: Remember the rhyme: "1 and 9, 2 and 8, 3 and 7, 4 and 6, 5 and 5 - all make 10!"
Addition properties:

• Commutative Property: a + b = b + a (order doesn't matter)

• Identity Property: a + 0 = a (adding zero doesn't change the number)

• Associative Property: (a + b) + c = a + (b + c) (grouping doesn't matter)

Solution: Exercises 4 to 5
4 Missing addend
Exercise 4
Find the missing number: ? + 5 = 10
Definition:

Missing addend: The unknown number that completes the addition equation to equal 10

Expression
? + 5 = 10
Inverse operation
10 - 5 = 5
Answer
5
Step 1: Recognize the problem

We need to find what number plus 5 equals 10

Step 2: Use subtraction to find the missing addend

10 - 5 = 5

Step 3: Verify the answer

5 + 5 = 10 ✓

5 + 5 = 10
Final answer:

5 + 5 = 10

Applied rules:

• Subtraction as inverse: To find a missing addend, subtract the known addend from the sum

• Number bond to 10: 5 + 5 is a special number bond

• Self-check: Always verify by adding to confirm the answer

5 Word problem
Exercise 5
Sarah has 6 apples. She needs 10 apples in total. How many more apples does she need?
Definition:

Word problem: A real-world situation that can be solved using math

Problem
6 + ? = 10
Solution
10 - 6 = 4
Answer
4 apples
Step 1: Identify what we know

Sarah has 6 apples and needs 10 total

Step 2: Set up the equation

6 + ? = 10

Step 3: Solve using subtraction

10 - 6 = 4

Step 4: Answer the question

Sarah needs 4 more apples

6 + 4 = 10
Final answer:

Sarah needs 4 more apples to have 10 apples in total

Applied rules:

• Word problem solving: Identify known information and what you need to find

• Subtraction as inverse: Use subtraction to find missing addends

• Real-world connection: Math helps us solve everyday problems

Addition Facts with Sum of 10 - Complete Summary
a + b = 10
Number Bonds to 10
Key definitions:

Addition: The operation of combining two or more numbers to find their total

Sum: The answer when you add numbers together

Addend: The numbers being added together

Number bond: A relationship showing how numbers combine to make a total

Complement: The number that, when added to another, equals a specific target (here, 10)

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

Complete methodology:
  1. Analyze the problem: Look for the target sum (10) and identify known/unknown numbers
  2. Choose the method: Counting on, using known number bonds, or subtraction as inverse
  3. Apply the method: Follow the steps of the chosen technique
  4. Verify the result: By adding or using another method
Tip 1: Master all number bonds to 10 - they're building blocks for other math.
Tip 2: Use the "making 10" strategy for other addition problems.
Tip 3: Practice with visual aids like ten frames or number lines.
Tip 4: Always check your work by adding from the first number.
Common errors: Forgetting that order doesn't matter in addition, starting to count from the first number instead of the next number.
Memory tip: Remember the number bond pairs: 1+9, 2+8, 3+7, 4+6, 5+5.
Number bonds to 10:

Complete set: 1+9=10, 2+8=10, 3+7=10, 4+6=10, 5+5=10, 6+4=10, 7+3=10, 8+2=10, 9+1=10

Patterns: Notice how the first number increases while the second decreases

Commutative property: Each bond works in both directions

Visualization: Number Bonds to 10
Number Bond Patterns
Consider the following number bond patterns:
1+9=10, 2+8=10, 3+7=10, 4+6=10, 5+5=10

Analysis: These patterns show important relationships in addition:

  • Number bonds to 10: Pairs that combine to equal 10
  • These facts serve as building blocks for more complex addition
  • Notice the symmetric pattern in the pairs

Questions & Answers

Question: Why do we need to learn number bonds to 10? Isn't it easier to just count everything?

Answer: Learning number bonds to 10 is like learning the foundation of a house - it makes everything else stronger! Here's why:

  • Speed: Knowing number bonds means you can solve problems instantly
  • Confidence: When you know these facts, math feels easier
  • Advanced math: You'll use these for bigger addition, subtraction, and multiplication
  • "Making 10" strategy: Number bonds help solve harder problems like 8 + 5 by thinking 8 + 2 + 3 = 10 + 3 = 13

Counting works for now, but number bonds help you solve harder problems later!

Question: My child knows 5 + 5 = 10, but struggles with finding the missing number in 5 + ? = 10. How can I help?

Answer: This is a common challenge! Your child knows the fact but struggles with the reverse thinking. Try these approaches:

  • Use what they know: "If 5 + 5 = 10, then what number goes with 5 to make 10?"
  • Counting up: Start at 5 and count up to 10 (6, 7, 8, 9, 10 - that's 5 more)
  • Subtraction: 10 - 5 = 5
  • Manipulatives: Use 10 objects, separate 5, count the remaining

The key is connecting what they already know to the new problem format!

Question: I sometimes forget if 7 + 3 = 10 or 7 + 4 = 10. How can I remember better?

Answer: Here are several memory tricks for number bonds to 10:

Method 1 - Counting:

  • Start at 7, count 3 more: 8, 9, 10
  • So 7 + 3 = 10

Method 2 - Partner thinking:

  • 7 and 3 are partners that make 10
  • Think of them as best friends who always go together

Method 3 - Visual pattern:

  • Notice that 7 + 3 uses the digits 7 and 3, which add up to 10
  • Or remember: "7 and 3 are friends who make 10"

Practice with all the number bonds until they feel automatic!

Question: How can I check if my answer is correct when finding missing addends?

Answer: Here are reliable methods to check missing addend problems:

Method 1 - Addition check:

  • Add your answer to the known addend
  • If you get the target number (10), your answer is correct
  • Example: For ? + 6 = 10, if you say 4, then 4 + 6 = 10 ✓

Method 2 - Subtraction check:

  • Take the known addend from the target number
  • Should equal your answer
  • Example: 10 - 6 = 4, so ? = 4

Method 3 - Counting:

  • Count from the known addend up to the target number
  • Should match your answer

These methods help build confidence and catch errors!

Question: What's the fastest way to learn all the number bonds to 10?

Answer: Here are the most effective strategies for mastering number bonds to 10:

  1. Learn them in pairs: Start with 1+9=10 and 9+1=10, then 2+8=10 and 8+2=10
  2. Look for patterns: Notice how one number increases while the other decreases
  3. Practice daily: Even 5 minutes a day makes a big difference
  4. Use games: Flashcards, apps, or online games make practice fun
  5. Connect to real life: Find examples of making 10 in daily activities

Remember: "1 and 9, 2 and 8, 3 and 7, 4 and 6, 5 and 5 - all make 10!"