Grade by Grade
Strand A: Foundations of Language and Mathematics · Numbers and Counting

Numbers 11 to 20

A6.3 A6.10 A6.8About 20 minutes
Learning goals
  • I can read and say the numbers 11 to 20.
  • I can write numbers to 20.
  • I know that 11 to 19 are 10 and some more, and 20 is two tens.
  • I can say one more and one less, and tell which number is bigger, up to 20.

Words to know

ten and some more
A full ten frame (10) and a few extra. 13 is 10 and 3 more.
teen numbers
13 to 19. We hear "teen" at the end, like fourteen. 11 and 12 have their own special names.
one more
The number that comes next when we count. One more than 14 is 15.
one less
The number just before. One less than 14 is 13.

Egg carton surprise!

Grown-up: read aloud.

We have a box of eggs. It holds 10 eggs, and it is full. Then we find 3 more eggs. How many eggs do we have now?

We don't need to count from 1. Say 10, then count on: 11, 12, 13.

A full egg carton holds ten brown eggs in two rows of five, with three more eggs on the table beside it.
The carton is full, so that is 10 eggs. Count on the eggs beside it: 11, 12, 13! AI-generated image
One full ten frame and 3 more. 10 and 3 more is 13.

Ten and some more

When a ten frame is full, we have 10.

The numbers 11 to 19 are all 10 and some more. Look at 13. The 1 at the front stands for the full ten. The 3 tells us there are 3 more.

20 is special. It is two full tens: 10 and 10.

NumeralSay itTen and some more
11eleven10 and 1
12twelve10 and 2
13thirteen10 and 3
14fourteen10 and 4
15fifteen10 and 5
16sixteen10 and 6
17seventeen10 and 7
18eighteen10 and 8
19nineteen10 and 9
20twenty10 and 10 (two full tens)
The numbers 11 to 20. Read down the first column, then say each one.
Worked example

Let's build 16

Let's show 16 with buttons and two ten frames.

  1. Fill the first ten frame. Count: 1, 2, 3 … 10. It is full.
  2. Now put buttons in the second ten frame. Say 10, then count on: 11, 12, 13, 14, 15, 16.
  3. How many in the second frame? 6.
  4. So 16 is 10 and 6 more.

16 is one full ten and 6 more.

16: one full ten frame and 6 more.
Worked example

Let's write 18

Let's write the number eighteen.

  1. Eighteen is 10 and 8 more.
  2. Write a 1 first. It stands for the full ten.
  3. Right beside it, write an 8. Keep them close together: 18.
  4. Read it back: "eighteen".

18: a 1, then an 8.

Tricky teens

When we say "fourteen", we hear the 4 first. But we write the 1 first: 14, not 41.

Also, "eleven" and "twelve" don't sound like "ten and one" or "ten and two". We just learn them by heart.

One more and one less

One more is the number that comes next when we count. One more than 14 is 15.

One less is the number that comes just before. One less than 14 is 13.

On a number line, one more is a hop to the right. One less is a hop to the left.

10111213141516171819201 more1 less
Start at 14. One more is 15. One less is 13.
Worked example

Which is more: 12 or 17?

Which number is more, 12 or 17?

  1. Find both numbers on the number line, or count: 12 comes before 17.
  2. Numbers that come later when we count are more.
  3. Think of ten frames: 12 is 10 and 2. 17 is 10 and 7. 7 more is more than 2 more.

17 is more than 12. 12 is less than 17.

Just for fun

What did the egg carton say when the 10th egg went in?

“I’m full! Any more eggs will have to start a new ten.” 🥚

Hands-on activity

Teen number builders and hopscotch

You need: two egg cartons with 2 cups taped over in each (so each has 10 cups), or two ten frames drawn on paper, about 20 small things (dry pasta, buttons, cereal), paper and a crayon. Chalk if you can go outside.

  1. Build it: the grown-up writes a number from 11 to 20. Fill one carton (10), then put the extra pieces in the second carton. Say "10 and __ more."
  2. Write it: now you write the number. Remember: the 1 goes first.
  3. One more, one less: add one piece. What number now? Take two away. What number now?
  4. Chalk hopscotch: draw a number line from 10 to 20 on the sidewalk. Stand on a number. The grown-up calls "one more!" or "one less!" and you hop.
  5. Calendar hunt: find the days 11 to 20 on a calendar.

Math talk: "How do you know 19 is more than 15?"

Safety: watch young children closely with small items.

Your turn

1

What number is 10 and 4 more?

2

Grown-up: write 12, 15 and 19 on paper. Point to fifteen.

3

Count from 11 to 20.

4

What is one more than 16?

5

What is one less than 13?

6

Write the number 11.

7

Which is more: 18 or 14?

More practice: warm-up

1

A full ten frame is how many?

2

One full ten frame and 1 more. What number is that?

3

What comes after 10?

4

Say this number: 20

5

Say this number: 13

More practice: on your own

1

How many?

🔵🔵🔵🔵🔵🔵🔵🔵🔵🔵

🔵🔵🔵🔵🔵

2

You want to build 17. You filled one ten frame. How many more do you need in the second frame?

3

What is one less than 20?

4

Write fourteen. Which numeral do you write first?

5

Which is less: 11 or 19?

Challenge

1

Put these in order from smallest to biggest: 17, 12, 15

2

Is 13 closer to 10 or to 20?

3

Kai wrote 61 for sixteen. What would you tell Kai?

Check your understanding

Quiz

1.

Which one is fourteen?

2.

10 and 2 more is …

3.

What is one more than 17?

4.

Which number is more?

5.

Two full ten frames make …

For parents and teachers

Big idea: Numbers 11 to 19 are 10 and some more, and 20 is two tens. Seeing a full ten frame plus extras helps children read, write and build these numbers. The Kindergarten Curriculum (2026) expects children to identify and write numbers to 20 and to understand how numbers from 0 to 20 relate (one more, one less, bigger and smaller, close to 10 or 20).

Common difficulties:

  • Reversing teen numbers (writing 41 for fourteen). We hear the 4 first, so this is very natural. Build the number with a full ten frame first, then write the 1 for the ten.
  • Eleven and twelve. They don't sound like "ten-one" and "ten-two". Practise them often.
  • Counting from 1 every time. Encourage starting at 10: "The carton is full, that's 10. Keep going."
  • Backwards numerals (like a backwards 7). Still very normal at this age.

How to help: Count to 20 on the stairs or while jumping. Point to dates 11 to 20 on the calendar. Ask "What's one more?" and "What's one less?" in daily life ("You have 15 crackers. If you eat one, how many?"). Egg cartons make great ten frames.