Key Stage 1 Mathematics Paper 1: Arithmetic (2025)

💡 What do we need to do?

We are asked to subtract (take away) 8 from 10.

Method 1: Number Bonds

We know our number bonds to 10. We know that \( 8 + 2 = 10 \).

So, \( 10 – 8 = 2 \).

Method 2: Counting Back

Start at 10 and count back 8 steps: 9, 8, 7, 6, 5, 4, 3, 2.

We need to add 4 to 45.

Since we are adding a single digit number (4) to a two-digit number (45), we should look at the ones column.

Method:

Start at 45 and count on 4: 46, 47, 48, 49.

Or, just add the ones: \( 5 + 4 = 9 \).

So, \( 45 + 4 = 49 \).

We are adding 40 and 12.

Let’s split 12 into tens and ones: \( 12 = 10 + 2 \).

First, add the 10 to 40:

\( 40 + 10 = 50 \)

Now, add the remaining 2:

\( 50 + 2 = 52 \)

We are taking 7 away from 68.

Look at the ones column: we have 8 ones in 68, and we want to take away 7.

\( 8 – 7 = 1 \)

The tens digit (60) stays the same because we are not crossing a ten boundary.

So, \( 68 – 7 = 61 \).

We are adding three numbers that are all multiples of 10.

We can just add the first digits and then put a 0 at the end.

We need to find \( 3 + 4 + 1 \).

\( 3 + 4 = 7 \)

\( 7 + 1 = 8 \)

So, 8 tens is 80.

Alternatively: \( 30 + 40 = 70 \). Then \( 70 + 10 = 80 \).

\( 8 \times 2 \) means “8 lots of 2” or “double 8”.

We can count in 2s eight times: 2, 4, 6, 8, 10, 12, 14, 16.

Or we can just double 8: \( 8 + 8 = 16 \).

We need to count in 5s seven times.

5, 10, 15, 20, 25, 30, 35.

So, \( 7 \times 5 = 35 \).

We know that \( 3 + 7 = 10 \).

So, using tens, \( 30 + 70 = 100 \).

Let’s count in tens from 30 to 100: 40, 50, 60, 70, 80, 90, 100.

That is 7 tens, which is 70.

We can write this in columns, lining up the tens and ones.

  33
+ 34
────

First, add the ones: \( 3 + 4 = 7 \).

Next, add the tens: \( 3 + 3 = 6 \).

  33
+ 34
────
  67

We can start with the larger number (29) and add 9.

Or we can round 29 to 30.

Method 1 (Bridge through 10):

Add 1 to 29 to make 30.

We have 8 left from the 9.

\( 30 + 8 = 38 \).

Method 2 (Adding):

\( 9 + 9 = 18 \)

So \( 9 + 29 = 38 \).

We start with 80. We take something away, and we are left with 50.

We need to find the difference between 80 and 50.

Count up from 50 to 80 in tens: 60, 70, 80.

That was 3 tens.

So, the missing number is 30.

Check: \( 80 – 30 = 50 \).

First, calculate \( 79 – 10 \).

When we subtract 10, the tens digit goes down by one, but the ones digit stays the same.

\( 79 – 10 = 69 \).

Now take away the second 10 from 69.

\( 69 – 10 = 59 \).

We have 70 and we need to get to 85.

Let’s count up from 70 to 85.

70 to 80 is 10.

80 to 85 is 5.

So we added \( 10 + 5 = 15 \).

We have 52 and want to take away 5.

2 is smaller than 5, so we will go below 50.

Let’s take away 2 first to get to 50.

\( 52 – 2 = 50 \)

We still need to take away 3 more (because \( 5 = 2 + 3 \)).

\( 50 – 3 = 47 \)

Finding \( \frac{1}{2} \) means splitting the number into 2 equal parts.

It is the same as dividing by 2.

We know that \( 2 + 2 = 4 \).

So, \( 20 + 20 = 40 \).

Half of 40 is 20.

We want to know how many 10s fit into 60.

Count in 10s until we reach 60: 10, 20, 30, 40, 50, 60.

That is 6 groups of 10.

So, \( 60 \div 10 = 6 \).

Write the numbers one above the other.

  16
+ 75
────

Add the ones: \( 6 + 5 = 11 \).

Write down the 1 and carry the 1 ten to the next column.

  16
+ 75
────
   1
  1

Add the tens: \( 1 + 7 = 8 \).

Don’t forget the carried 1: \( 8 + 1 = 9 \).

  16
+ 75
────
  91
  1

Dividing by 2 is the same as finding half.

We need to find half of 22.

Half of 20 is 10.

Half of 2 is 1.

\( 10 + 1 = 11 \).

Use column addition.

Add ones: \( 9 + 1 = 10 \).

Write 0 and carry 1.

  69
+ 21
────
   0
  1

Add tens: \( 6 + 2 = 8 \).

Add the carried 1: \( 8 + 1 = 9 \).

  69
+ 21
────
  90
  1

We can use columns.

\( 9 – 7 = 2 \).

  99
- 17
────
   2

\( 9 – 1 = 8 \).

So the answer is 82.

  99
- 17
────
  82

We need to find half of 26.

Let’s split 26 into tens and ones: 20 and 6.

Half of 20 is 10.

Half of 6 is 3.

Add them together: \( 10 + 3 = 13 \).

Use columns.

\( 7 + 8 = 15 \).

Write 5 and carry 1.

  57
+ 28
────
   5
  1

\( 5 + 2 = 7 \).

Add the carried 1: \( 7 + 1 = 8 \).

  57
+ 28
────
  85
  1

Finding a quarter is the same as halving and then halving again.

Or dividing by 4.

Half of 24 is 12.

Half of 12 is 6.

Alternatively, using times tables: \( 4 \times 6 = 24 \).

So, \( 24 \div 4 = 6 \).

We want to calculate \( 43 – 17 \).

Look at the ones: 3 is smaller than 7, so we need to exchange a ten.

  43
- 17
────

Take 1 ten from 40, leaving 30. The 3 ones become 13.

\( 13 – 7 = 6 \).

Then subtract the tens: \( 3 – 1 = 2 \).

  3413
- 1 7
──────
  2 6

To find the missing number, we can do the opposite (inverse).

Instead of adding 19, we subtract 19 from 64.

Calculate \( 64 – 19 \).

4 is less than 9, so exchange a ten.

14 take away 9 is 5.

5 tens take away 1 ten is 4 tens.

  5614
- 1 9
──────
  4 5