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

This is a multiples of ten which marks the tens boundary where the pattern of counting changes.

Crossing the tens boundary counting forwards

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

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

Match the rows on the one hundred square to the correct decade numbers on that row.

Lucas is counting forwards and taps this number on his Gattegno chart. What number will he tap next? 

Andeep is counting. What number will he say next? 

When counting forwards, which counting sequence is correct?

Look at the picture. I’m thinking of a number that ends in 4. When I count forwards, I say it after 40. What is my number?

Which of these rows from the one hundred square should come last when counting forwards? 

Sam is counting the rows on the one hundred square backwards. They count the forties, the thirties. Which row will they say next?

Sort these numbers in the order you would say them when counting forwards along the row of the one hundred square.

Sort these numbers in the order you would say when counting backwards along the row of the one hundred square.

Sam is counting along the sixties row. Which number will they say next?  

Numbers can be said in different ways. Match the numbers to the correct way to say it.

This lesson will soon be taken down.

Crossing the tens boundary counting forwards

Lesson outcome