Year 2 · 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.
These lessons were written around Australian Curriculum strands and matched to New Zealand year levels by age (NZ Year 1 is the first year of school). They are not yet mapped to The New Zealand Curriculum, so check them against your own learning programme.
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.