Count a large group of objects by counting tens and ones | Maths

Starter quiz

Which of the following describes the picture?

We have 4 groups of ten and 8 more ones.

We have 8 groups of ten and 4 more ones. ✓
Laura has put her cubes into groups of ten and has some more ones left over. Which place value chart represents her cubes?
How would you write the number eighty-nine in digits?

'89' ✓
Andeep has 54 straws. He puts them into groups of ten and there are some more ones left over. Which of the following could describe his group?

There are 4 groups of ten and 5 extra ones.

There are 5 groups of ten and 4 extra ones. ✓

There are 9 groups of ten and no extra ones.
Match the numbers that have the same value.

73

⇔

7 groups of ten and 3 more ones ✓

94

⇔

9 groups of ten and 4 more ones ✓

37

⇔

3 groups of ten and 7 more ones ✓

49

⇔

4 groups of ten and 9 more ones ✓
Andeep counts his pencils in ones. He has 37 pencils. If he puts them into groups of ten, how many extra ones will he have left over.

3

7 ✓

37

Exit quiz

Which of the following are true?

There are 6 groups of ten and 4 more ones.

There are 4 groups of ten and 6 more ones. ✓

There are 46 ones. ✓

There are 64 ones.
Which place value chart matches the one hundred square?
Which of the following represents the same value as the one hundred square?

74 ones ✓

47 ones

84 ones
Which of the following images represents the same value as the one hundred square?
Which of the following is true?

The number being shown is 65

The number being shown is 56 ✓

There are 5 tens and 6 ones ✓

There are 6 tens and 5 ones.
I’m thinking of a number which is on the one hundred square. It has more than 8 tens and it has 2 ones. What is my number?

'92' ✓

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Lesson Details

Key learning points

One item can be used to represent several other items. This is called unitising.
The order in which tens and ones are arranged does not affect the value of the number.
We can use a one hundred square to help find the value of two-digit numbers more efficiently.

Common misconception

Children may continue counting in tens when they reach the ones, e.g. count 2 tens and 3 ones completely in tens. They may think arrangement of tens and ones affects how to count them.

Make deliberate errors to prompt discussion and refer back to previous stem sentences, e.g. 'The objects are in ones, so I can count them in ones.' Present tens and ones in non-standard arrangements, so children practise always counting tens first.

Keywords

Unitising - Unitising means treating groups that contain, or represent, the same number of things as ‘ones’ or ‘units’. It is important in understanding place value and supports us to think multiplicatively.