Numbers to 100
Numbers to 100
You use numbers every day. In this unit you will say, read and write numbers from 0 to 100. Every 2-digit number is made of tens and ones.
Tens and ones
A 2-digit number has two places: ā¢ tens (the first digit) ā¢ ones (the last digit) Example: 34 is 3 tens and 4 ones. 3 tens is 30 and 4 ones is 4, so 30 + 4 = 34.
The value of each digit
Each digit has a value because of its place. In 53: ā¢ the 5 is worth 50 (5 tens) ā¢ the 3 is worth 3 (3 ones) So 53 = 50 + 3.
Reading and writing numbers
You can write numbers in words. 47 is 'forty-seven'. 62 is 'sixty-two'. Say the tens first, then the ones.
Counting on and back
On the 100 square you can count in steps of 1 and 10. ā¢ Counting on 1: 33, 34, 35, 36. Only the ones change. ā¢ Counting on 10: 22, 32, 42. Only the tens change; the ones stay the same. ā¢ Counting back 10: 52, 42, 32.
Worked examples
Tens and ones
- Look at 34.
- The first digit is tens: 3 tens is 30.
- The last digit is ones: 4 ones is 4.
Answer: 34 is 3 tens and 4 ones (30 + 4).
Value of a digit
- Look at 53.
- The 5 is in the tens place.
Answer: The value of the 5 is 50.
Writing a number in words
- Look at 47.
- Say the tens (forty), then the ones (seven).
Answer: 47 is 'forty-seven'.
Counting on in tens
- Start at 22.
- Counting on 10 adds one ten and keeps the ones the same.
Answer: 22 + 10 = 32.
Where you see this in real life
- You might live at house number 47.
- A book might have 64 pages.
- You might have collected 71 stickers.
Key words
- Digit
- One of the numerals 0 to 9 used to write a number.
- Tens
- The place of the first digit in a 2-digit number.
- Ones
- The place of the last digit in a 2-digit number.
- Place value
- The value a digit has because of its place in the number.
- 100 square
- A grid of the numbers 1 to 100 that helps you count and spot patterns.