Numbers to 100
Comparing and ordering numbers
Now that you know the numbers to 100, you can compare them and put them in order. You can also make number sequences and use ordinal numbers like 1st, 2nd and 3rd.
Comparing numbers
To compare two numbers, look at the tens first. 43 has 4 tens and 34 has 3 tens, so 43 is greater. 36 is more than 24 because 3 tens is more than 2 tens.
Greater than and less than
The sign > means 'greater than' and < means 'less than'. So 43 > 34 (43 is greater than 34) and 57 < 75 (57 is less than 75).
Ordering numbers
To put numbers in order, look at the tens. To order 67, 21 and 34 from smallest to greatest you get 21, 34, 67. A number line helps you see the order.
Number sequences
A sequence is a list of numbers that follow a rule. • Count on in tens: 37, 47, 57, 67, 77. • Count back in twos: 58, 56, 54, 52, 50. • Count back in tens: 74, 64, 54, 44, 34.
Ordinal numbers
Ordinal numbers tell you a position: 1st (first), 2nd (second), 3rd (third), 6th (sixth). The 2nd child is the second one in the line.
Worked examples
Which is greater?
- Compare 34 and 43.
- Look at the tens first: 43 has 4 tens, 34 has 3 tens.
- 4 tens is more than 3 tens.
Answer: 43 is the greater number.
Ordering numbers
- Put 67, 21 and 34 in order.
- Look at the tens: 21 has 2 tens, 34 has 3 tens, 67 has 6 tens.
Answer: In order they are 21, 34, 67.
A number sequence
- A sequence starts at 37 and counts on in tens.
- Add one ten each time: 37, 47, 57, 67, 77.
Answer: The next number after 57 is 67.
Ordinal numbers
- Start counting positions from the front.
- 1st, 2nd, 3rd, 4th, 5th, 6th.
Answer: The 6th child is the sixth one in the line.
Where you see this in real life
- There are more marbles in a box of 36 than in a bag of 24.
- Finding out who came 1st, 2nd and 3rd in a race.
- Putting house numbers in order along a street.
Key words
- Greater
- A number that is more than another number.
- Less
- A number that is smaller than another number.
- Order
- To put numbers in line from smallest to greatest, or greatest to smallest.
- Sequence
- A list of numbers that follow a rule, like counting on in tens.
- Ordinal number
- A number that tells a position, like 1st, 2nd or 3rd.