Numbers to 1000
Hundreds, tens and ones
We use numbers every day. In this unit you will explore numbers up to 1000. A 3-digit number is made up of hundreds, tens and ones.
The three places
A 3-digit number has three places: ā¢ hundreds (the first digit) ā¢ tens (the middle digit) ā¢ ones (the last digit) Example: 327 is 3 hundreds, 2 tens and 7 ones.
The value of each digit
Each digit has a value that depends on its place. In 327: ā¢ the 3 is worth 300 ā¢ the 2 is worth 20 ā¢ the 7 is worth 7 So 327 = 300 + 20 + 7. It helps to say the number out loud.
Number words
You can write numbers in words too. 472 is 'four hundred and seventy-two'. 358 is 'three hundred and fifty-eight'. Say the hundreds, then the tens, then the ones.
Counting on and back
You can count on and back in steps of 1 and 10 from any number. ā¢ Counting on 1: 499, 500. ā¢ Counting on 10 adds one ten: 458, 468, 478. ā¢ Counting back 10 takes one ten away: 295, 285, 275.
Worked examples
Value of a digit
- Look at 472. Say it: 'four hundred and seventy-two'.
- The 7 is in the tens place.
- The value of the 7 is 7 tens.
Answer: The value of the 7 is 70.
Breaking a number into parts
- Look at 925.
- The 9 is 9 hundreds (900), the 2 is 2 tens (20), the 5 is 5 ones (5).
Answer: 925 = 900 + 20 + 5.
Writing a number in words
- Look at 358.
- Say the hundreds (three hundred), then the tens and ones (fifty-eight).
Answer: 358 is 'three hundred and fifty-eight'.
Counting on in tens
- Start at 772.
- Counting on 10 adds one ten.
Answer: 772 + 10 = 782.
Where you see this in real life
- There are 365 days in a year.
- You might live at house number 321.
- A book might have 180 pages.
Key words
- Digit
- One of the numerals 0 to 9 used to write a number.
- Hundreds
- The place of the first digit in a 3-digit number.
- Tens
- The place of the middle digit in a 3-digit number.
- Ones
- The place of the last digit in a 3-digit number.
- Place value
- The value a digit has because of its place in the number.