Answer Key for Money Word Problems in Grade 3

Complete solutions, methods, and explanations for all money word problems with step-by-step solutions.

Answers: Problems 1 to 3
1 Addition Problem
Problem 1
Emma saved $4.75 last week and $3.25 this week. How much money did she save in total?
Definition:

Problem Type: Addition of money amounts

Solution Method:
  1. Identify the amounts to add: $4.75 and $3.25
  2. Align decimal points and add
  3. Carry over if cents exceed 100
  4. Verify the answer
Amount 1
$4.75
Amount 2
$3.25
Total
$4.75 + $3.25 = $8.00
Step 1: Write amounts vertically

$4.75
+ $3.25

Step 2: Add the cents

75¢ + 25¢ = 100¢ = $1.00

Step 3: Add the dollars

$4 + $3 + $1 (carried over) = $8

Step 4: Combine dollars and cents

$8 + $0.00 = $8.00

Correct Answer: $8.00

Verification: $8.00 - $3.25 = $4.75 ✓

Final answer:

Emma saved $8.00 in total

Key Points:

• Decimal Alignment: Align decimal points when adding

• Carrying: When cents exceed 100, carry over to dollars

• Verification: Check by subtracting one addend from the sum

2 Subtraction Problem
Problem 2
Marcus had $10.00. He spent $6.45 on a video game. How much money does he have left?
Definition:

Problem Type: Subtraction of money amounts

Starting Amount
$10.00
Amount Spent
$6.45
Remaining
$10.00 - $6.45 = $3.55
Step 1: Write amounts vertically

$10.00
- $6.45

Step 2: Borrow if needed

$10.00 becomes $9.100¢ (since we need to borrow)

Step 3: Subtract the cents

100¢ - 45¢ = 55¢

Step 4: Subtract the dollars

$9 - $6 = $3

Correct Answer: $3.55

Verification: $3.55 + $6.45 = $10.00 ✓

Final answer:

Marcus has $3.55 left

Key Points:

• Borrowing: When subtracting, borrow from the next place value

• Decimal Alignment: Align decimal points when subtracting

• Verification: Check by adding the difference to the subtrahend

3 Multiplication Problem
Problem 3
Sarah earns $2.50 each day for 4 days. How much money does she earn in total?
Definition:

Problem Type: Multiplication of money amounts

Daily Earnings
$2.50
Number of Days
4
Total Earnings
$2.50 × 4 = $10.00
Step 1: Identify the repeated amount

Sarah earns $2.50 each day

Step 2: Identify the number of times

She works for 4 days

Step 3: Multiply

$2.50 × 4 = $10.00

Step 4: Check with addition

$2.50 + $2.50 + $2.50 + $2.50 = $10.00 ✓

Correct Answer: $10.00

Verification: $10.00 ÷ 4 = $2.50 ✓

Final answer:

Sarah earns $10.00 in total

Key Points:

• Repeated Addition: Multiplication is adding the same number multiple times

• Decimal Multiplication: Count decimal places in the answer

• Verification: Check with division or repeated addition

Answer Key Summary
\(\text{Correct Answer} = \text{Solution Process}\)
Verification Method
Addition
A + B = C
Check: C - B = A
Subtraction
A - B = C
Check: C + B = A
Multiplication
A × B = C
Check: C ÷ B = A
Division
A ÷ B = C
Check: C × B = A
✅
Correct: $8.00
✅
Correct: $3.55
✅
Correct: $10.00
Answers: Problems 4 to 5
4 Division Problem
Problem 4
Four friends found $8.00 together and want to share it equally. How much does each friend get?
Definition:

Problem Type: Division of money amounts

Total Amount
$8.00
Number of Friends
4
Each Gets
$8.00 ÷ 4 = $2.00
Step 1: Identify the total amount

They found $8.00

Step 2: Identify the number of parts

There are 4 friends

Step 3: Divide the total by the number of parts

$8.00 ÷ 4 = $2.00

Step 4: Check with multiplication

$2.00 × 4 = $8.00 ✓

Correct Answer: $2.00 per friend

Verification: $2.00 × 4 = $8.00 ✓

Final answer:

Each friend gets $2.00

Key Points:

• Equal Sharing: Division splits a total into equal parts

• Decimal Division: Divide as if whole numbers, then place decimal

• Verification: Check with multiplication

5 Mixed Operations
Problem 5
Tom earned $5.00 from mowing lawns. He spent $1.75 on candy. Then he earned $3.00 more from helping neighbors. Finally, he shared the remaining money equally with his sister. How much did each get?
Definition:

Problem Type: Mixed operations problem

Started With
$5.00
Spent
-$1.75
Earned More
+$3.00
Remaining
=?
Step 1: Calculate after first transaction

$5.00 - $1.75 = $3.25

Step 2: Calculate after earning more

$3.25 + $3.00 = $6.25

Step 3: Divide equally between 2 people

$6.25 ÷ 2 = $3.125 ≈ $3.13

Step 4: Check the calculation

$3.13 × 2 = $6.26 (rounded from $6.25)

Correct Answer: $3.13 each

Verification: $3.13 × 2 = $6.26 ≈ $6.25 ✓

Final answer:

Tom and his sister each get $3.13

Key Points:

• Order of Operations: Perform operations from left to right

• Mixed Operations: Handle one operation at a time

• Rounding: Money typically rounded to nearest cent

Solution Strategies and Verification
\(\text{Verification} = \text{Inverse Operation}\)
Checking Your Answers
Key definitions:

Verification: Checking if your answer is correct using inverse operations

Inverse Operations: Operations that undo each other (addition/subtraction, multiplication/division)

Answer Key: Correct solutions with step-by-step explanations

Answer key methodology:
  1. Solve step-by-step: Show all work clearly
  2. Provide correct answer: State the final answer
  3. Verify solution: Check using inverse operation
  4. Identify key points: Highlight important concepts
Tip 1: Always show your work step-by-step.
Tip 2: Verify your answer using the inverse operation.
Tip 3: Include units (dollars and cents) in your answer.
Tip 4: Check if your answer makes sense in the problem context.
Common errors: Misaligning decimals, choosing wrong operation, calculation mistakes.
Verification strategies: Use inverse operations, estimate to check reasonableness.
Answer key verification formulas:

• Addition: Sum - Addend = Other Addend

• Subtraction: Difference + Subtrahend = Minuend

• Multiplication: Product ÷ Factor = Other Factor

• Division: Quotient × Divisor = Dividend

Questions & Answers

Question: How do I know if my answer is correct when solving money word problems?

Answer: Use inverse operations to verify your answer:

  • For addition: Subtract one addend from the sum to get the other addend
  • For subtraction: Add the difference to the subtrahend to get the minuend
  • For multiplication: Divide the product by one factor to get the other factor
  • For division: Multiply the quotient by the divisor to get the dividend

Example: If $4.75 + $3.25 = $8.00, check: $8.00 - $3.25 = $4.75 ✓

Question: What should I do if my answer doesn't match the answer key?

Answer: Follow these steps when your answer differs:

  • Review the problem: Read it again to ensure you understood correctly
  • Check your work: Go through each step carefully
  • Identify the error: Look for calculation mistakes or wrong operation
  • Try again: Solve the problem from scratch
  • Verify: Use the inverse operation to check

Don't get discouraged - mistakes help you learn!

Question: How can I help students understand the importance of showing their work?

Answer: Explain the benefits of showing work:

  • Tracking errors: Makes it easier to find mistakes
  • Partial credit: Teachers can award points for correct steps
  • Learning: Helps reinforce the problem-solving process
  • Verification: Allows checking each step of the solution

Use the answer key as a model for showing clear, organized work.

Comprehensive Summary: Money Word Problems Answer Key
Key Concepts and Definitions:

Answer Key: A collection of correct solutions with detailed explanations and verification steps

Verification: Checking if your answer is correct using inverse operations

Inverse Operations: Operations that undo each other (addition/subtraction, multiplication/division)

Step-by-Step Solutions: Breaking problems into manageable parts with clear explanations

Core Rules and Principles:

• Show Work: Always demonstrate your solution process clearly

• Verify Answers: Use inverse operations to check your work

• Include Units: Always include dollar signs and cents in your answer

• Check Reasonableness: Ensure your answer makes sense in the problem context

Answer Key Creation Method:
  1. Solve the problem: Work through each step carefully
  2. State the answer: Clearly identify the final solution
  3. Verify the solution: Use inverse operations to confirm
  4. Highlight key points: Note important concepts or common mistakes
Tip 1: Always align decimal points when adding or subtracting money.
Tip 2: When subtracting, borrow from the next place value if needed.
Tip 3: For multiplication, count decimal places in the final answer.
Tip 4: Always verify your answer using the inverse operation.
Common Pitfalls: Misaligning decimals, choosing wrong operation, calculation errors, skipping verification.
Practice Strategies: Work with real money, practice all operations separately, verify answers.
Key Takeaways for Students:

• Always show your work step-by-step to track your thinking

• Use inverse operations to verify your answers

• Include units (dollars and cents) in your final answer

• Check that your answer makes sense in the context of the problem

• Practice regularly to build confidence with all operations