Number and Place Value

Welcome to Year 3 Number and Place Value!

Welcome to an exciting journey into the world of numbers! In Year 3, we move beyond small numbers and start exploring numbers all the way up to \(1,000\). Understanding how numbers are built is like learning the secret code of math. Once you know how place value works, you will be able to read, write, and compare huge numbers with ease!

Why is this important? We use numbers every single day—when we count pocket money, check the time, or look at house numbers on a street. Let’s get started!

1. Understanding 3-Digit Numbers

Every number is made up of digits. In a 3-digit number, the position (place) of each digit tells us how much it is worth. We call this Place Value.

Think of a number like a house with three rooms:
• The Hundreds room (H)
• The Tens room (T)
• The Ones room (O)

Let’s look at the number \(342\):
• The \(3\) is in the Hundreds column, so it means \(300\).
• The \(4\) is in the Tens column, so it means \(40\).
• The \(2\) is in the Ones column, so it means \(2\).

So, \(342 = 300 + 40 + 2\). This is called partitioning (breaking a number apart).

Quick Review:
What is the value of the \(5\) in \(519\)?
It is in the Hundreds place, so it is worth five hundred (\(500\))!

Key Takeaway: The position of a digit changes its value. A \(5\) in the ones place is just \(5\), but a \(5\) in the hundreds place is \(500\)!

2. Reading and Writing Numbers to \(1,000\)

In Year 3, we practice writing numbers using both digits (like \(256\)) and words (like two hundred and fifty-six).

A helpful tip: When writing numbers in words, we usually use the word "and" after the hundreds. For example: \(704\) is seven hundred and four.

Common Mistake to Avoid: Don't forget the placeholder zero! In the number \(405\), the zero tells us there are "no tens." If we forgot the zero, it would look like \(45\), which is a much smaller number!

Did you know? The number \(1,000\) is the first 4-digit number we meet. It is made of \(10\) hundreds!

3. Comparing and Ordering Numbers

To compare numbers, we look at which one is bigger or smaller. We use these special symbols:
• \(>\) means Greater Than (bigger)
• \(<\) means Less Than (smaller)
• \(=\) means Equal To (the same)

The Hungry Alligator Trick:
Imagine the symbol is an alligator’s mouth. The alligator is very hungry, so he always wants to eat the biggest number!
Example: \(542 > 399\). The mouth opens toward \(542\) because it is larger.

How to compare numbers:
1. Look at the Hundreds first. The number with more hundreds is bigger.
2. If the hundreds are the same, look at the Tens.
3. If the tens are also the same, look at the Ones.

Key Takeaway: Always start comparing from the left (the largest place value column).

4. Counting in Steps (4, 8, 50, and 100)

Counting isn't just for \(1, 2, 3\)! In Year 3, we learn to skip-count in different sizes.

Counting in 4s and 8s

If you know your 4 times table, you can count in 4s: \(4, 8, 12, 16, 20...\)
Top Tip: To count in 8s, you can just double your 4s! Because \(8\) is double \(4\), the numbers in the 8 times table are always even.

Counting in 50s

Counting in 50s is like counting in 5s, but with a zero on the end:
\(50, 100, 150, 200, 250, 300...\)

Counting in 100s

This is the easiest one! Only the hundreds digit changes:
\(100, 200, 300, 400, 500...\)

Don't worry if this seems tricky at first! Patterns are like puzzles. Once you see the "jump" between numbers, you'll be a skip-counting pro.

5. Finding 10 or 100 More or Less

Sometimes we need to quickly add or subtract \(10\) or \(100\) from a number. We don't even need a calculator for this!

Finding 10 more or less:
Only the Tens digit changes. (Unless you have to "bridge" a hundred!)
Example: \(10\) more than \(345\) is \(355\). \(10\) less than \(345\) is \(335\).

Finding 100 more or less:
Only the Hundreds digit changes.
Example: \(100\) more than \(621\) is \(721\). \(100\) less than \(621\) is \(521\).

Key Takeaway: When finding \(100\) more or less, the tens and ones digits usually stay exactly the same!

Summary Checklist

Before you finish this chapter, make sure you can:
• Explain what each digit in a 3-digit number is worth (H, T, O).
• Read and write numbers up to \(1,000\) in words and digits.
• Use the \(>\) and \(<\) symbols to compare numbers.
• Count forward and backward in steps of \(4, 8, 50,\) and \(100\).
• Quickly find \(10\) or \(100\) more or less than any number.

Well done! You are becoming a master of numbers!