Solved Exercises on How to Multiply Numbers by 10 in Grade 3

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

Solution: Exercises 1 to 3
1 Single Digit by 10
Exercise 1
Problem: How do you multiply 7 by 10?
Definition:

Multiplying by 10: A multiplication operation where one factor is 10

Method for Multiplying by 10:
  1. Take the original number (7)
  2. Move each digit one place to the left
  3. Add a zero in the ones place
  4. Result: 7 × 10 = 70
Original
7
Multiply by 10
× 10
Result
70
Step 1: Identify the number to multiply

We want to multiply 7 by 10

Step 2: Understand what multiplying by 10 means

Multiplying by 10 means we have 10 groups of the number

Step 3: Apply the place value rule

When multiplying by 10, each digit moves one place to the left

Step 4: Add a zero in the ones place

The 7 moves from ones place to tens place, zero fills the ones place

Step 5: Write the result

7 × 10 = 70

7 × 10 = 70
Final answer:

When you multiply 7 by 10, you get 70.

Explanation: The digit 7 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

7
Ones Place
Before
→
Shift Left
Multiply by 10
7
Tens Place
After
0
Ones Place
Added Zero
2 Two-Digit Number by 10
Exercise 2
Problem: How do you multiply 24 by 10?
Definition:

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

Original
24
Multiply by 10
× 10
Result
240
Step 1: Identify each digit and its place

In 24: 2 is in tens place, 4 is in ones place

Step 2: Understand the multiplication

24 × 10 means 10 groups of 24

Step 3: Apply place value shift

2 moves from tens to hundreds place, 4 moves from ones to tens place

Step 4: Add zero in ones place

Zero fills the empty ones place after shifting

Step 5: Write the result

24 × 10 = 240

24 × 10 = 240
Final answer:

When you multiply 24 by 10, you get 240.

Explanation: The digit 2 moves from tens place to hundreds place, the digit 4 moves from ones place 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
4
×
1
0
=
2
4
0
3 Three-Digit Number by 10
Exercise 3
Problem: How do you multiply 365 by 10?
Definition:

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

Original
365
Multiply by 10
× 10
Result
3650
Step 1: Identify each digit and its place

In 365: 3 is in hundreds place, 6 is in tens place, 5 is in ones place

Step 2: Understand the multiplication

365 × 10 means 10 groups of 365

Step 3: Apply place value shift

3 moves from hundreds to thousands place, 6 moves from tens to hundreds place, 5 moves from ones to tens place

Step 4: Add zero in ones place

Zero fills the empty ones place after shifting

Step 5: Write the result

365 × 10 = 3650

365 × 10 = 3650
Final answer:

When you multiply 365 by 10, you get 3650.

Explanation: Each digit moves one place to the left: 3 from hundreds to thousands, 6 from tens to hundreds, 5 from ones to tens, and 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
Hundreds
Original
6
Tens
Original
5
Ones
Original
→
Shift
Multiply by 10
3
Thousands
Shifted
6
Hundreds
Shifted
5
Tens
Shifted
0
Ones
Added
Multiplying by 10 Concepts and Rules
n × 10 = n with 0 appended
Multiplying by 10 Formula
Rule
Place Shift
Digits move left
Rule
Zero Add
Add 0 at end
Rule
Value ×10
10 times larger
Rule
Base 10
Our number system
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

Base 10 system: Our number system based on groups of 10

Expanded form: Writing numbers to show place value (e.g., 24 = 20 + 4)

Multiplying by 10 Method:
  1. Identify the number: Recognize the number being multiplied by 10
  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: Just add a zero to the end of the number when multiplying by 10.
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: This works for any number, regardless of how many digits it has.
Common errors: Forgetting to add the zero, shifting digits incorrectly, or misunderstanding place value.
Practice areas: Place value understanding, digit shifting, visualizing the multiplication process.
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 Decimal Number by 10
Exercise 4
Problem: How do you multiply $3.50 by 10?
Definition:

Decimal multiplication by 10: Moving the decimal point one place to the right

Original
$3.50
Multiply by 10
× 10
Result
$35.00
Step 1: Identify the decimal number

We want to multiply $3.50 by 10

Step 2: Understand decimal place value

In $3.50: 3 is in ones place, 5 is in tenths place, 0 is in hundredths place

Step 3: Apply the decimal multiplication rule

When multiplying by 10, move the decimal point one place to the right

Step 4: Move each digit

3 moves from ones to tens place, 5 moves from tenths to ones place, 0 moves from hundredths to tenths place

Step 5: Write the result

$3.50 × 10 = $35.00

$3.50 × 10 = $35.00
Final answer:

When you multiply $3.50 by 10, you get $35.00.

Explanation: The decimal point moves one place to the right, making the number 10 times larger.

Applied rules:

• Decimal shift: Move decimal point one place to the right when multiplying by 10

• Value multiplication: The number becomes 10 times larger

• Money context: Same rules apply to monetary amounts

💰
$3.50
Original
→
Decimal Shift
Multiply by 10
💰
$35.00
Result
5 Large Number by 10
Exercise 5
Problem: How do you multiply 4,287 by 10?
Definition:

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

Original
4,287
Multiply by 10
× 10
Result
42,870
Step 1: Identify each digit and its place

In 4,287: 4 is in thousands place, 2 is in hundreds place, 8 is in tens place, 7 is in ones place

Step 2: Understand the multiplication

4,287 × 10 means 10 groups of 4,287

Step 3: Apply place value shift

4 moves from thousands to ten-thousands place, 2 moves from hundreds to thousands place, 8 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 after shifting

Step 5: Write the result

4,287 × 10 = 42,870

4,287 × 10 = 42,870
Final answer:

When you multiply 4,287 by 10, you get 42,870.

Explanation: Each digit moves one place to the left: 4 from thousands to ten-thousands, 2 from hundreds to thousands, 8 from tens to hundreds, 7 from ones to tens, and 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
Thou
Original
2
Hun
Original
8
Ten
Original
7
One
Original
→
Shift
Multiply by 10
4
Ten-Thou
Shifted
2
Thou
Shifted
8
Hun
Shifted
7
Ten
Shifted
0
One
Added
Multiplying Numbers by 10 Summary
Comprehensive Summary of Multiplying Numbers 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 each digit one place to the left when multiplying by 10.

Base 10 system: Our number system based on groups of 10.

Decimal point movement: Moving the decimal point one place to the right when multiplying decimals by 10.

Core Rules and Principles:

• 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.

• Decimal movement: Move decimal point one place to the right for decimal numbers.

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

Step-by-Step Methods:

1. Identify the number: Recognize the number being multiplied by 10.

2. Understand place value: Know the position of each digit.

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

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

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

Examples from Simple to Advanced:

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

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

Intermediate: 24 × 10 = 240 (2 moves from tens to hundreds, 4 moves from ones to tens, zero fills ones)

Advanced: 365 × 10 = 3650 (3 moves from hundreds to thousands, 6 from tens to hundreds, 5 from ones to tens, zero fills ones)

Complex: $3.50 × 10 = $35.00 (decimal point moves one place right)

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!