Use Coins to Identify Missing Tens or Ones

In this activity, we will be adding coins. 

 

We will be adding 10ps and 1ps. We can think about place value to help us work these out .

 

 

Let's add up these coins together:

 

  

 

In the tens column, we count the coins in tens. There are 4 of these coins so we need to count in tens 4 times:

10, 20, 30, 40 

So, we have 40p in the tens column. 

 

Now, let's count the ones column. There are 7 of these coins so we need to count in ones 7 times:

1, 2, 3, 4, 5, 6, 7

So, we have 7p in the ones column. 

 

Now we can just put the tens and ones together: 40 + 7 = 47p

 

Example

Can you add the coins together to work out the missing number in the calculation below? Write the number in the box below.

 

 

?

+

1

=

21

 

What is missing in this number sentence?

We have the total as that number is after the equals sign. 

We have the ones as these are the numbers that are only one digit - there is one 1p so that makes 1p! 

 

This means we are missing the 10ps. Count how many 10ps there are and that is the missing number. 

There are two 10ps, so this means that 20p is missing. 

 

20

+

1

=

21

 

Let's get started!