Year 1 · Mathematics · Number
Numbers to 120: tens and ones
Counting, reading and writing numbers to 120, and understanding that a two-digit number is made of tens and ones.
Awaiting educator review. This material was drafted by our content team with AI assistance and is waiting for review by a qualified educator. Please check it suits your child before using it. Created 10 October 2026.
Learning goals
Learners will
- Count forwards and backwards by ones from any number up to 120.
- Count by tens from 0 to 120.
- Show a two-digit number as tens and ones using bundles and loose objects.
Success looks like
- I can count on from any number to 120.
- I can count by tens to 120.
- I can show a number like 34 as 3 tens and 4 ones.
- I can say which of two numbers is bigger.
The big idea
Counting a big pile one at a time is slow and easy to lose track of. Grouping objects into tens makes large numbers much easier to count and to understand.
Give your child a pile of pop sticks. Ask them to count out 10 and put a rubber band around them to make a bundle. Keep making bundles until there are not enough sticks left to make another one.
Now count the bundles by tens — 10, 20, 30 — and then count on the loose sticks by ones. For 3 bundles and 4 loose sticks, say '10, 20, 30, 31, 32, 33, 34.'
Show how the number is written. In 34, the 3 tells us there are 3 tens and the 4 tells us there are 4 ones. The position of a digit changes its value: 34 and 43 use the same digits but are different numbers.
When there are 10 bundles of ten, we have 100. Keep counting past 100: 101, 102 … up to 120. Many children say 'one hundred and ten' as 110; let them build it with 11 bundles to see why.
To compare two numbers, look at the tens first. 71 has 7 tens and 17 has only 1 ten, so 71 is greater.
- Count tens first, then ones.
- In a two-digit number, the left digit shows tens and the right digit shows ones.
Worked examples
Counting a big pile of pasta
A pile of pasta tubes is grouped into 5 bundles of ten with 7 loose tubes left over. How many tubes are there?
- Count the bundles by tens: 10, 20, 30, 40, 50.
- Count on the loose tubes by ones: 51, 52, 53, 54, 55, 56, 57.
- 5 tens and 7 ones is written as 57.
Answer: There are 57 pasta tubes.
Which number is bigger?
Which is bigger, 48 or 84?
- 48 has 4 tens and 8 ones.
- 84 has 8 tens and 4 ones.
- Compare the tens first: 8 tens is more than 4 tens.
Answer: 84 is bigger than 48.
Counting past 100
Count on 3 from 108.
- Start at 108 and keep it in your head.
- Count on three: 109, 110, 111.
Answer: 3 more than 108 is 111.
Practice check
Have a go, then check your answers. Each answer comes with an explanation.
Answer guide for parents
There are 3 bundles of ten pop sticks and 4 loose sticks. How many sticks altogether?
34 — 3 tens is 30, and 4 ones more makes 34.
What number comes straight after 99?
100 — After 99 we have 10 tens, which is 100.
In the number 58, what does the 5 stand for?
5 tens — The 5 is in the tens place, so it means 5 tens, which is 50.
What number is 6 tens and 2 ones?
62 — 6 tens is 60, plus 2 ones makes 62.
Which number is bigger: 17 or 71?
71 — 71 has 7 tens and 17 has only 1 ten, so 71 is bigger.
Count by tens and fill the gap: 40, 50, 60, ___
70 — Counting by tens, after 60 comes 70.
Which number comes between 109 and 111?
110 — Counting 109, 110, 111 — the number in between is 110.
How many tens are there in 90?
9 — Counting by tens to 90: 10, 20, 30, 40, 50, 60, 70, 80, 90 is 9 tens.
Watch out for
- Writing 'one hundred and five' as 1005. Build it with 10 bundles and 5 loose sticks to show it is 105.
- Thinking 34 and 43 are the same because they use the same digits. Build both with bundles to compare.
- Losing track when counting over a 'decade' (for example 29, 30). Practise counting across tens slowly with a hundreds chart or a tape measure.
Tips for parents
- Keep the bundles of ten — they are useful all year for adding, subtracting and comparing.
- A tape measure is a handy number line for counting to 120 and beyond.
- Ask your child to show numbers in more than one way: with bundles, by writing it, and by saying it.
Go further
- Make a hundreds chart on paper and play 'guess my number' using clues such as 'it has 4 tens and is odd'.
- Count a jar of coins or buttons by grouping into tens first, then estimate the total before counting the next jar.
- Count by tens starting from a number other than 0, such as 3, 13, 23, 33.