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Watch: Counting forward and backwards from twenty

Let's practise counting forward and backwards, to and from twenty and learn why some numbers end in 'teen'.

1 to 20

Let’s count together from 1 to 20. Then count back from 20 to 0.

Use the grid below to help you as you count.

What do you notice about the second row of numbers?

They are all two digit numbers.

Now let's have a look at how each number can be represented with blocks.

Look at the blocks on the top row and the bottom row.

Can you see that the red blocks are the same in both rows. However, on the bottom row, each number has a yellow tens block.

Showing 20 on a number line

We can use a number line to help us with counting as well.

Here are the numbers 1 to 20 shown on a number line.

Reading numbers

It's easy to see patterns when the numbers 0 to 20 are shown like above. However, sometimes it is hard to ‘hear’ a pattern when we are counting the teen numbers.

Look at the table below. On the left you will find the numbers in order from 10 to 20 in words.

On the right you will see the same numbers but described as tens and ones.

Think about the pattern in the numbers from 13 to 19. These are teen numbers.

Teen numbers are different because the teen sound (which means ten) comes after the ones sound.

Remember

Remember that the ones sound in sixteen comes before the tens, but the number is still built from 1 ten and 6 ones. -

When you write the number in numerals, the tens come before the ones.

Activity 1

• Can you count on and back without looking at the number line to help you?

• Can you start counting on from 10 and stop at 18?

• Can you say 18?

• Can you write 18 in numbers and words?

• What number comes after 18? Can you write it in numbers and words?

• What number comes before 18? Can you write it in number and words?

Activity 2