Learning Objectives
By the end of this lesson, you will be able to:
- Read and write numbers up to 100,000 in numerals and words (Objectives 1-3)
- State the value of each digit in numbers up to 100,000 (Objectives 4-5)
- Partition numbers using expanded notation (Objectives 6-7)
- Round numbers to the nearest 10, 100, and 1000 (Objectives 8-9)
- Compare and order numbers up to 100,000
SEA Tip
Place value questions appear in Section I of the SEA Math paper. These are often the first questions and are easy marks! (SEA Framework Page 21-22)
Watch: Place Value
Start by watching this video to learn about place value. Take notes as you watch! 📝
Place Value – Mathematics Video Lesson
Quick Check
Did you understand the video? Review the notes below before continuing! ✅
Place Value
Place value tells us the value of each digit in a number based on its position!
Place Value Positions
- Ones: Rightmost position (1s)
- Tens: Second position from right (10s)
- Hundreds: Third position from right (100s)
- Thousands: Fourth position from right (1,000s)
- Ten Thousands: Fifth position from right (10,000s)
📊 Place Value Chart:
| Ten Thousands |
Thousands |
Hundreds |
Tens |
Ones |
| 10,000 |
1,000 |
100 |
10 |
1 |
| 4 |
7 |
3 |
5 |
2 |
| 40,000 |
7,000 |
300 |
50 |
2 |
Number: 47,352 = Forty-seven thousand, three hundred and fifty-two
📊 Example 1: Finding the Value of a Digit
What is the value of 7 in 47,352?
Solution:
- Identify the position: 7 is in the thousands place
- Calculate the value: 7 × 1,000 = 7,000
- Answer: 7,000
Answer: 7,000
Memory Trick
Start from the RIGHT and move LEFT: Ones → Tens → Hundreds → Thousands → Ten Thousands
Expanded Notation
Expanded notation shows the value of each digit in a number!
📋 Two Ways to Write Expanded Notation:
Example: 47,352
Method 1: Addition Form
47,352 = 40,000 + 7,000 + 300 + 50 + 2
Method 2: Multiplication Form
47,352 = (4 × 10,000) + (7 × 1,000) + (3 × 100) + (5 × 10) + (2 × 1)
📊 Example 2: Writing in Expanded Notation
Write 85,609 in expanded notation
Solution:
- Identify each digit’s value:
- 8 = 80,000 (ten thousands)
- 5 = 5,000 (thousands)
- 6 = 600 (hundreds)
- 0 = 0 (tens)
- 9 = 9 (ones)
- Write in addition form: 80,000 + 5,000 + 600 + 0 + 9
Answer: 80,000 + 5,000 + 600 + 9
Rounding Numbers
Rounding helps us estimate numbers to the nearest 10, 100, or 1000!
Rounding Rules
- Look at the digit to the RIGHT of the place you’re rounding to
- If it’s 0-4: Round DOWN (keep the digit the same)
- If it’s 5-9: Round UP (add 1 to the digit)
- Change all digits to the RIGHT to zeros
📊 Example 3: Rounding to Nearest 100
Round 4,738 to the nearest 100
Solution:
- Identify the hundreds digit: 7
- Look at the digit to the right: 3
- 3 is 0-4, so round DOWN: 7 stays 7
- Change digits to the right to zeros: 4,700
Answer: 4,700
📊 Example 4: Rounding to Nearest 1000
Round 47,352 to the nearest 1000
Solution:
- Identify the thousands digit: 7
- Look at the digit to the right: 3
- 3 is 0-4, so round DOWN: 7 stays 7
- Change digits to the right to zeros: 47,000
Answer: 47,000
Common Mistake
Don’t forget: 5 or more rounds UP! Many students round down when they see 5.
Lesson Complete!
Great job finishing Lesson 1.1! You’re mastering place value for the SEA exam! 🎉
Continue to Lesson 1.2