House of Hundreds – I

Imagine a big house where every room holds hundreds of things! In this chapter we explore numbers more deeply — learning about the hundreds, tens, and ones structure, comparing large numbers, and working with number lines up to 1000.

• Building Numbers with Hundreds
• We can think of a number like a house:
• The ground floor is the ones (0–9)
• The first floor is the tens (10–90)
• The top floor is the hundreds (100–900)

A 3-digit number is built as: H × 100 + T × 10 + O × 1

For example: 4 hundreds + 7 tens + 3 ones = 473

1. 1.Comparing Numbers
2. 2.To compare two 3-digit numbers:
3. 3.Compare hundreds digits first.
4. 4.If equal, compare tens digits.
5. 5.If still equal, compare ones digits.

Use symbols: > (greater than), < (less than), = (equal to)

Number Line up to 1000
On a number line, numbers increase from left to right. The halfway point between 0 and 1000 is 500.

Rounding to the Nearest 10
- If the ones digit is 5 or more, round up.
- If the ones digit is less than 5, round down.
Example: 47 → rounds to 50 (ones digit 7 ≥ 5, round up)
Example: 63 → rounds to 60 (ones digit 3 < 5, round down)

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Example 1: Building a number
Write the number with 6 hundreds, 0 tens, and 8 ones.
6 × 100 + 0 × 10 + 8 × 1 = 608

Example 2: Comparing numbers
Compare 765 and 756.
Hundreds: 7 = 7. Tens: 6 > 5. So 765 > 756.

Example 3: Number line
Which number is halfway between 300 and 400?
Halfway = (300 + 400) ÷ 2 = 700 ÷ 2 = 350

Example 4: Rounding to nearest 10
Round 384 to the nearest 10.
Ones digit = 4 (less than 5), round down → 380

Example 5: Ordering numbers
Arrange 528, 582, 258, 825 from least to greatest.
Compare hundreds: 258 (2) < 528 (5) = 582 (5) < 825 (8).
Compare 528 and 582: tens digit 2 < 8, so 528 < 582.
Order: 258, 528, 582, 825

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• Key Reminders
• 10 ones = 1 ten; 10 tens = 1 hundred; 10 hundreds = 1 thousand (1000)
• The number just before 1000 is 999.
• Zero is important as a placeholder: 308 ≠ 38.