This is where the pattern of counting changes at the start of the number to show a new decade has started.

The point at which the counting moves from one decade into another.

This is a multiple of ten which mark the tens boundary where the pattern of counting changes.

Crossing the tens boundary counting backwards 

Maths

In this unit pupils will extend their learning by counting to 100. They will explore the pattern in counting and focus on the end of the decade and the start of the new decade numbers.  In the future unit pupils will explore the counting sequence for counting to 100 and beyond and represent the numbers from 20-99 in different ways, including marking the position on a number line.

In prior learning, pupils will have verbally counted beyond 20, recognising the pattern of the counting system. In this unit pupils will extend their learning by counting to 100 and exploring the pattern in counting.

Pattern in counting from 20 to 100

Which row on the one hundred square is before the thirties?

The pattern of counting changes when you __________.

Match each decade number to the correct number that comes before it.

Sort these numbers in the order you would say them when counting backwards.

Aisha is counting backwards from  the decade number 40. Which numbers will she say next?

Lucas counts back from 50. Which of these numbers won't he say?

On a one hundred square, a number ending in a 9 is always followed by a __________.

Match each decade number to the end of the correct row of the one hundred square.

Sort these numbers in the order you would say them when counting forwards.

Aisha is counting forwards. She is saying how many tens each number has. After 6 tens 9, what will she say?

Which one of these counting sequences is not correct when counting backwards.

This lesson will soon be taken down.

Crossing the tens boundary counting backwards

Lesson outcome