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Did you complete Lesson 1.1? Review Place Value & Expanded Notation →
Learning Objectives
By the end of this lesson, you will be able to:
- Round whole numbers to the nearest 10, 100, 1000, 10,000, 100,000, and 1,000,000 (Objective 10)
- Differentiate between factors and multiples (Objective 11)
- Identify prime and composite numbers (Objective 11)
- Calculate square numbers up to 144 (Objectives 12-13)
SEA Tip
These concepts appear in Section I and II of the SEA Math paper. Master them to secure easy marks! (SEA Framework Page 21-22)
Watch: Rounding Whole Numbers
Start by watching this video to learn how to round numbers to any place value. Take notes as you watch! 📝
Quick Check
Did you understand the video? Review the notes below before continuing! ✅
Rounding to Any Place Value
Rounding helps us estimate numbers quickly. In the SEA exam, you’ll need to round to 10s, 100s, 1000s, 10,000s, 100,000s, and 1,000,000s.
🎯 Rounding Place Values:
Tens
10
Hundreds
100
Thousands
1,000
Ten Thousands
10,000
Hundred Thousands
100,000
Millions
1,000,000
📋 The Rounding Rule:
- Find the digit in the place you’re rounding TO
- Look at the neighbor to the right
- If the neighbor is 0-4 → Round DOWN (keep the digit)
- If the neighbor is 5-9 → Round UP (add 1 to the digit)
- Change all digits to the right to ZERO
📊 Examples:
| Number | Round To | Look At | Answer |
|---|---|---|---|
| 452,387 | Nearest 10 | 7 (5-9) | 452,390 ↑ |
| 452,387 | Nearest 100 | 8 (5-9) | 452,400 ↑ |
| 452,387 | Nearest 1,000 | 3 (0-4) | 452,000 ↓ |
| 452,387 | Nearest 10,000 | 2 (0-4) | 450,000 ↓ |
| 452,387 | Nearest 100,000 | 5 (5-9) | 500,000 ↑ |
| 452,387 | Nearest 1,000,000 | 4 (0-4) | 0 ↓ |
Common Mistake
Don’t forget to change ALL digits to the right to zero! 452,387 rounded to the nearest thousand is 452,000 NOT 452.
Watch: Factors and Multiples
Now watch this video to learn the difference between factors and multiples. This is a VERY important SEA topic! 🎯
Factors and Multiples
Understanding factors and multiples is essential for the SEA exam. Let’s break it down! 🔍
📌 What’s the Difference?
| Concept | Definition | Example |
|---|---|---|
| Factor | A number that divides another number evenly (no remainder) | Factors of 12: 1, 2, 3, 4, 6, 12 |
| Multiple | The result of multiplying a number by any whole number | Multiples of 3: 3, 6, 9, 12, 15… |
Prime Numbers
Exactly 2 factors: 1 and itself
2, 3, 5, 7, 11, 13, 17, 19, 23…
Composite Numbers
More than 2 factors
4, 6, 8, 9, 10, 12, 14, 15…
Memory Trick
Factors are FEW (they divide INTO the number). Multiples are MANY (they go ON FOREVER)! 🧠
Watch: Prime and Composite Numbers
Watch this video to learn how to identify prime and composite numbers. Remember: 1 is NEITHER prime nor composite! 💡
Watch: Square Numbers
Watch this video to learn about square numbers up to 144. You MUST memorize these for the SEA! 💪
Square Numbers up to 144
A square number is the result of multiplying a number by itself. For the SEA, you need to know square numbers up to 144 (12²).
🎯 Square Numbers Chart:
SEA Tip
Memorize these 12 square numbers! They appear frequently in Section I questions. Flashcards help! 📇
Quick Quiz
Test your understanding! Select an answer for each question. 🎯
0/6
Lesson Complete!
Great job finishing Lesson 1.2! You’re mastering number concepts for the SEA exam! 🎉
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