Numbers up to 1000
Primary 3 · Mathematics
Numbers up to 1000
Lesson 2 of 3
12 min
The head teacher asks Keza to count the new exercise books. They are packed in three ways: big boxes of 100, small bundles of 10, and a few loose books lying on the table.
Keza counts 4 boxes, 6 bundles and 2 loose books. She writes 462 on the board — and the head teacher smiles, because that is exactly right.
How did three little numbers turn into 462? That is what place value is.
In a three-digit number there are three seats. Each seat has a name.
| Hundreds | Tens | Ones |
|---|---|---|
| 4 | 6 | 2 |
So 462 means 4 hundreds, 6 tens and 2 ones — 4 boxes, 6 bundles, 2 loose books.
The digit 4 is small on the page, but it is sitting in the hundreds seat. So it is not worth 4. It is worth 400.
| Digit | Its seat | What it is worth |
|---|---|---|
| 4 | hundreds | 400 |
| 6 | tens | 60 |
| 2 | ones | 2 |
Add the three values back together and you get your number:
462 = 400 + 60 + 2
That is called breaking the number apart, or expanded form.
Step 1 Write the digits into their seats.
| Hundreds | Tens | Ones |
|---|---|---|
| 7 | 3 | 8 |
Step 2 Say what each one is worth. The 7 is in the hundreds seat, so it is worth 700. The 3 is in the tens seat, so it is worth 30. The 8 is in the ones seat, so it is worth 8.
Step 3 Write it out.
738 = 700 + 30 + 8 — that is 7 hundreds, 3 tens and 8 ones.
Watch the digit 8 travel between the seats:
| Number | Where the 8 sits | What the 8 is worth |
|---|---|---|
| 843 | hundreds | 800 |
| 384 | tens | 80 |
| 438 | ones | 8 |
Same digit every time. Different seat, different worth. The seat is the boss.
Now do the job backwards. Somebody gives you the parts and you build the number.
6 hundreds + 4 tens + 0 ones
Put 6 in the hundreds seat, 4 in the tens seat, 0 in the ones seat. That gives 640.
5 hundreds + 0 tens + 9 ones
Put 5 in the hundreds seat. There are no tens, so a 0 sits in the tens seat and keeps it warm. Then 9 in the ones seat.
That gives 509.
If you were lazy and left the zero out, you would write 59. But 59 is fifty-nine — a tiny number! The zero is not nothing. The zero is a guard, standing in an empty seat so the other digits cannot slide out of place.
Tip
How to remember it. The digit tells you how many. The seat tells you how much.
In 391, the 9 is only one digit — but it is sitting in the tens seat, so it is worth 90. Always ask yourself: which seat is it in?
Try each one, then tap Show answer to check.
Break 526 into hundreds, tens and ones.
Answer: 5 hundreds, 2 tens and 6 ones, that is 500 + 20 + 6.
What is the value of the 9 in 391?
Answer: 90. The 9 is sitting in the tens seat, so it means 9 tens.
Build the number: 8 hundreds + 0 tens + 3 ones.
Answer: 803. The 0 guards the empty tens seat. (803, not 83!)
400 + 70 + 6 = ?
Answer: 476. 4 hundreds, 7 tens, 6 ones.
Which digit is in the tens seat in 650?
Answer: 5. The 6 is in the hundreds seat and the 0 is in the ones seat, so the middle digit, 5, is the tens.
What you learned today
Quick check
What is the 7 worth in 274?
