Solved Exercises on Expanded Solutions for Grade 1

Master expanded solutions: place value decomposition, number representation, and mathematical expressions through these 5 detailed exercises.

Solution: Exercises 1 to 3
1 Complete Solution Process
Exercise 1
Solve: Write the expanded form of 35 step by step.
Show all solution steps.
Definition:

Expanded solution: A complete solution that shows every step needed to find the answer, including identification, calculation, and verification.

Method:
  1. Identify the number (35)
  2. Identify place values (tens, ones)
  3. Calculate value of each digit
  4. Write expanded form
  5. Verify the solution
TENS
3
→
ONES
5
Step 1: Identify the number
The number is 35
Step 2: Identify place values
3 is in the tens place
5 is in the ones place
Step 3: Calculate digit values
3 tens = 3 × 10 = 30
5 ones = 5 × 1 = 5
Step 4: Write expanded form
35 = 30 + 5
Step 5: Verify solution
30 + 5 = 35 ✓
35 = 30 + 5
Final answer:

The expanded form of 35 is 30 + 5

Applied rules:

• Step-by-step rule: Show all solution steps clearly

• Place value rule: Each position has a specific value

• Verification rule: Always check your answer

Tip: Write each step clearly to avoid mistakes.
2 Detailed Solution with Verification
Exercise 2
Solve: Write the expanded form of 64 and verify your answer.
Show all steps and verification process.
Definition:

Complete verification: Checking that the expanded form adds up to the original number to ensure accuracy.

TENS
6
→
ONES
4
Step 1: Identify the number
The number is 64
Step 2: Identify place values
6 is in the tens place
4 is in the ones place
Step 3: Calculate digit values
6 tens = 6 × 10 = 60
4 ones = 4 × 1 = 4
Step 4: Write expanded form
64 = 60 + 4
Step 5: Verify solution
60 + 4 = 64 ✓
The answer is correct!
64 = 60 + 4
Final answer:

The expanded form of 64 is 60 + 4, verified by adding 60 + 4 = 64

Applied rules:

• Verification rule: Always check that expanded parts sum to original number

• Completeness rule: Show all solution steps

• Accuracy rule: Verification ensures correct answers

3 Solution with Multiple Approaches
Exercise 3
Solve: Write 82 in expanded form using different approaches.
Show traditional method and word form.
Definition:

Multiple approaches: Solving the same problem using different methods to deepen understanding.

TENS
8
→
ONES
2
Approach 1: Traditional Method
Step 1: 8 tens = 8 × 10 = 80
Step 2: 2 ones = 2 × 1 = 2
Step 3: 82 = 80 + 2
Approach 2: Word Form
Step 1: Eighty-two = eighty + two
Step 2: Eighty-two = 80 + 2
Approach 3: Verification
80 + 2 = 82 ✓
82 = 80 + 2 (both approaches yield same result)
Final answer:

82 = 80 + 2 (verified through multiple approaches)

Applied rules:

• Different approaches rule: Same problem can be solved multiple ways

• Consistency rule: All approaches should yield same result

• Verification rule: Multiple approaches increase confidence in answer

Rules and methods, laws,...
35 = 30 + 5
Expanded Solution
🔍
Identify
Find the number
📊
Place Value
Tens and ones
➕
Addition
Combine values
✅
Verify
Check answer
Key definitions:

Expanded solution: A complete solution showing all steps to find the answer

Place value: The value of a digit based on its position in the number

Verification: Checking that the solution is correct

Tens: Groups of 10 (the left digit in a two-digit number)

Ones: Single units (the right digit in a two-digit number)

Complete methodology:
  1. Identify the problem: What number do you need to expand?
  2. Determine place values: Tens and ones for two-digit numbers
  3. Calculate digit values: Multiply each digit by its place value
  4. Write expanded form: Add the calculated values together
  5. Verify solution: Check that expanded parts sum to original number
Tip 1: Write each step clearly to avoid mistakes.
Tip 2: Always verify your answer by adding the expanded parts.
Tip 3: Use multiple approaches to check your work.
Common errors: Forgetting to multiply by place value, skipping verification step.
Memory aid: "I-D-C-A-V" - Identify, Determine, Calculate, Add, Verify.
Formulas to know by heart:

• Two-digit number AB = (A × 10) + B

• Tens value = tens digit × 10

• Ones value = ones digit × 1

• Verification: Expanded parts should sum to original number

Detailed Summary of Expanded Solutions
Key Concepts and Definitions:
  • Expanded Solution: A complete solution showing all steps to find the answer
  • Place Value: The value of a digit based on its position in the number
  • Verification: Checking that the solution is correct by confirming expanded parts sum to original number
  • Step-by-Step Process: Following a logical sequence to solve problems
  • Multiple Approaches: Solving the same problem using different methods
Core Rules and Principles:
  • Completeness Rule: Show all solution steps clearly
  • Verification Rule: Always check that expanded parts equal the original number
  • Place Value Rule: Each position has a specific value (tens, ones)
  • Accuracy Rule: Verification ensures correct answers
  • Systematic Rule: Follow a consistent method for all problems
Step-by-Step Method:
  1. Identify: Determine what number needs to be expanded
  2. Determine Place Values: Identify tens and ones positions
  3. Calculate Digit Values: Multiply each digit by its place value
  4. Write Expanded Form: Add the calculated values together
  5. Verify Solution: Check that expanded parts sum to original number
Examples:
  • Simple: 35 = 30 + 5
  • Medium: 64 = 60 + 4
  • Advanced: 82 = 80 + 2
Tips and Tricks:
  • Write Clearly: Keep each step separate and clear
  • Always Verify: Add expanded parts to confirm original number
  • Use Visuals: Draw blocks or charts to help understand
  • Check Work: Use multiple approaches when possible
Key Notes for Memorization:
  • IDCAV Method: Identify, Determine, Calculate, Add, Verify
  • Two-digit ABCD = (A × 10) + D for any two-digit number
  • Verification Essential: Always add expanded parts to check
  • Place Matters: Left digit is tens, right digit is ones
Solution: Exercises 4 to 5
4 Solution with Error Correction
Exercise 4
Solve: Write the expanded form of 57.
Show solution, identify common errors, and correct them.
Definition:

Error correction: Identifying and fixing common mistakes in expanded form solutions.

TENS
5
→
ONES
7
Correct Solution Steps:
Step 1: Identify number - 57
Step 2: Place values - 5 tens, 7 ones
Step 3: Calculate - 5 × 10 = 50, 7 × 1 = 7
Step 4: Write - 57 = 50 + 7
Step 5: Verify - 50 + 7 = 57 ✓
Common Errors to Avoid:
Error 1: 57 = 5 + 7 (wrong - ignores place value)
Error 2: 57 = 50 + 70 (wrong - wrong ones value)
Error 3: 57 = 5 + 70 (wrong - mixed up values)
Correction Process:
Always remember: tens digit × 10, ones digit × 1
57 = 50 + 7 (correct solution)
Final answer:

The expanded form of 57 is 50 + 7. Common error is forgetting that 5 tens = 50, not 5.

Applied rules:

• Error identification rule: Recognize common mistakes

• Correction rule: Show why common errors are wrong

• Verification rule: Always check final answer

5 Comprehensive Solution
Exercise 5
Solve: Write the expanded form of 91 in multiple formats.
Include numeric, word, and verification formats.
Definition:

Comprehensive solution: Providing the answer in multiple formats to demonstrate complete understanding.

TENS
9
→
ONES
1
Numeric Format:
Step 1: 9 tens = 9 × 10 = 90
Step 2: 1 one = 1 × 1 = 1
Step 3: 91 = 90 + 1
Word Format:
Ninety-one = ninety + one
Ninety-one = 90 + 1
Verification:
90 + 1 = 91 ✓
Visual Representation:
91 = [9 tens] + [1 one]
91 = 90 + 1 (all formats agree)
Final answer:

Numeric: 91 = 90 + 1
Word: Ninety-one = ninety + one
Verified: 90 + 1 = 91 ✓

Applied rules:

• Multi-format rule: Present solution in various formats

• Consistency rule: All formats should yield same result

• Verification rule: Check answer across all formats

Place Value Concepts: Expanded Solutions
35 = 30 + 5
Expanded Solution
Key definitions:

Place value: The value of a digit based on its position in the number (tens, ones)

Expanded solution: A complete solution showing all steps to find the answer

Verification: Checking that the solution is correct by confirming expanded parts sum to original number

Tens: Groups of 10 (the left digit in a two-digit number)

Ones: Single units (the right digit in a two-digit number)

Complete methodology:
  1. Identify the problem: What number do you need to expand?
  2. Determine place value: Tens place (left) or ones place (right)
  3. Calculate value: Multiply each digit by its place value
  4. Express in expanded form: Add the calculated values together
  5. Verify solution: Check that expanded parts sum to original number
Tip 1: Write each step clearly to avoid mistakes.
Tip 2: Always verify by adding the expanded parts.
Tip 3: Practice with concrete materials before moving to abstract numbers.
Tip 4: Use multiple approaches to check your work.
Common errors: Forgetting to multiply by place value, mixing up tens and ones, skipping verification.
Exam preparation: Know how to show all solution steps, verify answers, and avoid common mistakes.
Formulas to know by heart:

• Two-digit number AB = (A × 10) + B

• Tens value = tens digit × 10

• Ones value = ones digit × 1

• Verification: Expanded parts should sum to original number

🔍
Identify
Find the number
📊
Place Value
Tens and ones
➕
Addition
Combine values
✅
Verify
Check answer

Questions & Answers

Question: Why do I need to show all the steps when solving expanded form problems? Can't I just write the answer?

Answer: Showing all steps is very important for several reasons:

  • Understanding: It helps you understand what you're doing, not just getting the answer
  • Mistake catching: If you make an error, showing steps helps you find where you went wrong
  • Learning: It builds good habits for solving harder problems later
  • Checking: Teachers can see your thinking and help if needed

Think of it like showing your work in a recipe - it helps you learn and improves your skills!

Question: How can I help my child develop good expanded solution habits?

Answer: Here are effective strategies to help your child develop good expanded solution habits:

  • Model the process: Show them how you solve problems step by step
  • Create templates: Use worksheets with labeled steps to guide them
  • Encourage verbalization: Have them explain each step out loud
  • Practice regularly: Daily short practice sessions build habits
  • Celebrate progress: Praise careful work, not just correct answers

Focus on the process, not just the final answer. Good habits developed now will help in future math learning.

Question: What should I do if I make a mistake in my expanded solution?

Answer: Making mistakes is completely normal and helpful for learning! Here's what to do:

  • Don't panic: Mistakes help you learn better
  • Check your work: Go back through each step carefully
  • Look for patterns: Are you making the same type of mistake?
  • Ask for help: Talk to your teacher or parent about the mistake
  • Try again: Use what you learned to solve it correctly

Remember: The most important thing is to learn from mistakes, not avoid them!