Solved Exercises on How to Explain Multiplying by 10 in Grade 3

Master multiplying by 10: place value concepts, multiplication strategies, and visual representations through these 5 detailed exercises.

Solution: Exercises 1 to 3
1 Place Value Shift
Exercise 1
Problem: Explain how to multiply 4 by 10 using place value.
Definition:

Place value shift: When multiplying by 10, each digit moves one place to the left

Place Value Method:
  1. Identify the original number (4)
  2. Recognize that multiplying by 10 shifts digits one place left
  3. Add a zero in the ones place
  4. Result: 4 × 10 = 40
Original
4
Shift Left
→
Add Zero
40
Step 1: Start with the number

4 is in the ones place

Step 2: Multiply by 10

Each digit moves one place to the left

Step 3: Add zero in ones place

4 moves from ones to tens place, zero fills ones

Step 4: Write the result

4 × 10 = 40

4 × 10 = 40
Final answer:

When you multiply 4 by 10, you get 40.

Explanation: The digit 4 moves from the ones place to the tens place, and a zero fills the ones place.

Applied rules:

• Place value shift: Each digit moves one place to the left when multiplying by 10

• Zero insertion: A zero is added in the ones place after shifting

• Value multiplication: The number becomes 10 times larger

4
Ones Place
Before
→
Move Left
Multiply by 10
4
Tens Place
After
0
Ones Place
Added Zero
2 Two-Digit Number
Exercise 2
Problem: Explain how to multiply 23 by 10 using place value.
Definition:

Two-digit multiplication: Each digit in the number moves one place to the left when multiplied by 10

Original
23
Shift Left
→
Add Zero
230
Step 1: Identify each digit's place

2 is in the tens place, 3 is in the ones place

Step 2: Multiply by 10

Each digit moves one place to the left

Step 3: Shift each digit

2 moves from tens to hundreds place, 3 moves from ones to tens place

Step 4: Add zero in ones place

Zero fills the empty ones place

Step 5: Write the result

23 × 10 = 230

23 × 10 = 230
Final answer:

When you multiply 23 by 10, you get 230.

Explanation: Each digit moves one place to the left. The 2 moves from tens to hundreds place, the 3 moves from ones to tens place, and a zero fills the ones place.

Applied rules:

• Place value shift: Each digit moves one place to the left when multiplying by 10

• Zero insertion: A zero is added in the ones place after shifting

• Value multiplication: The number becomes 10 times larger

2
3
×
10
=
2
3
0
3 Visual Representation
Exercise 3
Problem: Explain 5 × 10 using visual groups of ten.
Definition:

Grouping by tens: Multiplying by 10 creates groups of ten

5 groups of
10
Total
50
Step 1: Think of 5 groups

Imagine you have 5 separate groups

Step 2: Each group has 10

Each group contains 10 items

Step 3: Count all items

Group 1: 10, Group 2: 10, Group 3: 10, Group 4: 10, Group 5: 10

Step 4: Add all groups

10 + 10 + 10 + 10 + 10 = 50

Step 5: Write the result

5 × 10 = 50

5 × 10 = 50
Final answer:

When you multiply 5 by 10, you get 50.

Explanation: This is the same as having 5 groups of 10, which equals 50.

Applied rules:

• Repeated addition: 5 × 10 = 10 + 10 + 10 + 10 + 10

• Grouping: Multiplication is repeated addition of equal groups

• Value multiplication: The number becomes 10 times larger

ParallelGroups
5 groups
Groups
10
per group
Items per Group
50
total
Total Items
Multiplying by 10 Concepts and Rules
n × 10 = n0
Multiplying by 10 Rule
Concept
Place Value
Digit shifts left
Concept
Zero Added
Rightmost digit
Concept
Value Increases
10 times larger
Concept
Visual Groups
Groups of 10
Key definitions:

Multiplying by 10: A mathematical operation that increases a number's value by a factor of 10

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

Digit shift: Moving digits to the left when multiplying by 10

Repeated addition: Multiplication as adding the same number multiple times

Multiplying by 10 Method:
  1. Identify the number: Recognize the number being multiplied
  2. Shift digits: Move each digit one place to the left
  3. Add zero: Place a zero in the rightmost position
  4. Verify: Check that the result is 10 times larger
Tip 1: When multiplying by 10, just add a zero to the end of the number.
Tip 2: Each digit moves one place value to the left (ones to tens, tens to hundreds).
Tip 3: The result is always 10 times larger than the original number.
Tip 4: Visualize it as making 10 copies of the original number.
Common errors: Forgetting to add the zero, shifting digits incorrectly, or misunderstanding place value.
Practice areas: Place value understanding, digit shifting, visualizing groups of 10.
Digit Shift: Each digit moves one place to the left
Zero Addition: Add zero in the ones place
Value Increase: Number becomes 10 times larger
Visual Groups: Think of 10 equal groups
Place Value Shift: abc × 10 = abc0
Place Value Formula
Solution: Exercises 4 to 5
4 Three-Digit Number
Exercise 4
Problem: Explain how to multiply 347 by 10 using place value.
Definition:

Three-digit multiplication: Each digit in the number moves one place to the left when multiplied by 10

Original
347
Shift Left
→
Add Zero
3470
Step 1: Identify each digit's place

3 is in the hundreds place, 4 is in the tens place, 7 is in the ones place

Step 2: Multiply by 10

Each digit moves one place to the left

Step 3: Shift each digit

3 moves from hundreds to thousands place, 4 moves from tens to hundreds place, 7 moves from ones to tens place

Step 4: Add zero in ones place

Zero fills the empty ones place

Step 5: Write the result

347 × 10 = 3470

347 × 10 = 3470
Final answer:

When you multiply 347 by 10, you get 3470.

Explanation: Each digit moves one place to the left. The 3 moves from hundreds to thousands place, the 4 moves from tens to hundreds place, the 7 moves from ones to tens place, and a zero fills the ones place.

Applied rules:

• Place value shift: Each digit moves one place to the left when multiplying by 10

• Zero insertion: A zero is added in the ones place after shifting

• Value multiplication: The number becomes 10 times larger

3
Hunds → Thous
Shift
4
Tens → Hunds
Shift
7
Ones → Tens
Shift
0
Ones
Added
5 Real-World Application
Exercise 5
Problem: If a book costs $6, how much would 10 books cost? Explain using place value.
Definition:

Real-world multiplication: Applying multiplication by 10 to practical scenarios

One Book
$6
Multiply by 10
× 10
Ten Books
$60
Step 1: Identify the cost of one item

One book costs $6

Step 2: Multiply by the number of items

We want 10 books

Step 3: Apply place value shift

6 moves from ones to tens place, zero fills ones place

Step 4: Write the result

6 × 10 = 60, so 10 books cost $60

10 books cost $60
Final answer:

Ten books would cost $60.

Explanation: Using place value, when you multiply $6 by 10, the 6 moves from the ones place to the tens place, and a zero fills the ones place, giving $60.

Applied rules:

• Place value shift: Each digit moves one place to the left when multiplying by 10

• Real-world context: Applying mathematical concepts to practical problems

• Value multiplication: The cost becomes 10 times larger

📚
1 book
Quantity
💰
$6
Cost
➡️
×10
Multiply
📚📚
10 books
Total
💰
$60
Cost
Multiplying by 10 Summary
Comprehensive Summary of Multiplying by 10
Definitions of Key Concepts:

Multiplying by 10: A mathematical operation that increases a number's value by a factor of 10.

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

Digit shift: Moving digits one position to the left when multiplying by 10.

Zero insertion: Adding a zero in the ones place after multiplying by 10.

Value multiplication: The result is always 10 times larger than the original number.

Core Rules and Principles:

• Place value shift: Each digit moves one place to the left when multiplying by 10.

• Zero addition: A zero is always added in the rightmost position.

• Value increase: The result is always 10 times the original number.

• Position importance: The position of each digit determines its value.

Step-by-Step Methods:

1. Identify the number: Recognize the number you want to multiply by 10.

2. Shift digits left: Move each digit one place value to the left.

3. Add zero: Place a zero in the ones place after shifting.

4. Verify result: Check that the number is 10 times larger.

5. Apply context: Use the result in the problem's context.

Examples from Simple to Advanced:

Simple: 1 × 10 = 10 (1 moves from ones to tens, zero fills ones)

Basic: 5 × 10 = 50 (5 moves from ones to tens, zero fills ones)

Intermediate: 23 × 10 = 230 (2 moves from tens to hundreds, 3 moves from ones to tens, zero fills ones)

Advanced: 456 × 10 = 4560 (4 moves from hundreds to thousands, 5 moves from tens to hundreds, 6 moves from ones to tens, zero fills ones)

Tips and Tricks:

• Quick method: Simply add a zero to the end of the number.

• Visual aid: Imagine moving each digit one place to the left.

• Check work: Divide your answer by 10 to see if you get the original number.

• Understand why: Each place value is 10 times larger than the previous one.

Common Pitfalls to Avoid:

• Forgetting to add the zero in the ones place after shifting digits

• Confusing which direction to shift digits (always left)

• Misunderstanding that the number becomes 10 times larger, not just bigger by 10

• Not recognizing that place value changes the value of each digit

Key Notes and Takeaways for Memorization:

• Multiplying by 10 always adds one zero to the end of the number

• Each digit moves one place value to the left (ones → tens → hundreds)

• The result is always 10 times the original number

• This works for any number, regardless of how many digits it has

• Understanding place value is key to mastering this concept

n × 10 = n with 0 appended
Multiplication by 10 Formula
🔢
Identify
Number
←
Shift
Left
0
Add
Zero
✅
Result
10×

Questions & Answers

Question: Why does multiplying by 10 always add a zero to the end of the number?

Answer: This happens because of our base-10 number system:

  • Our number system has 10 digits (0-9)
  • Each place value is 10 times larger than the one to its right
  • When you multiply by 10, each digit moves to a place value that's 10 times larger
  • The ones place becomes empty, so we fill it with zero

Example: 24 × 10 → 2 moves from tens to hundreds, 4 moves from ones to tens, zero fills the empty ones place = 240

Question: What happens if I multiply a number like 10 by 10? Do I add two zeros?

Answer: No, you still only add one zero when multiplying by 10:

  • 10 × 10 = 100 (not 1000)
  • Each digit moves one place to the left
  • The 1 moves from tens to hundreds place
  • The 0 moves from ones to tens place
  • A new zero fills the empty ones place

Remember: You multiply by 10 once, so you add one zero, regardless of how many zeros were in the original number.

Question: Can I multiply by 10 the same way with really big numbers?

Answer: Yes! The same rule applies to any number, no matter how big:

  • Every digit moves one place to the left
  • A zero is added in the ones place
  • The result is always 10 times larger than the original

Examples: 123 × 10 = 1230, 4567 × 10 = 45670, 89012 × 10 = 890120

The pattern is always the same: shift left, add zero!