2024 Key Stage 1 Mathematics Paper 1: Arithmetic

💡 What do we need to do?

We need to subtract 5 from 9. This means we start with 9 and take away 5.

Method:

Put 9 in your head and count back 5 fingers.

9… 8, 7, 6, 5, 4.

💡 Strategy:

We are adding 10 to 42. When we add 10, the “ones” digit (2) stays the same, but the “tens” digit (4) goes up by 1.

4 tens + 1 ten = 5 tens.

The ones stay as 2.

So, 42 becomes 52.

💡 What does this mean?

This means “4 groups of 2” or “double 4”.

We can count in 2s four times:

2, 4, 6, 8.

Or we can add 4 + 4 = 8.

We need to add three numbers. It is easier to add two numbers first, and then add the last one.

First, let’s do \( 55 + 5 \).

Counting in 5s: 55… 60.

Now we have 60. We need to add the last 5.

\( 60 + 5 = 65 \).

💡 Hint:

We know that \( 3 + 4 = 7 \).

So, 3 tens + 4 tens = 7 tens.

30 is 3 tens.

40 is 4 tens.

3 tens + 4 tens = 7 tens.

7 tens is 70.

Let’s add 30 and 10 first.

\( 30 + 10 = 40 \)

Now we add 50 to our answer of 40.

\( 40 + 50 = 90 \)

This means “4 groups of 5”. Let’s count in 5s four times.

5, 10, 15, 20.

Always start from the right side.

\( 3 + 3 = 6 \)

Now add the tens column.

\( 1 + 2 = 3 \)

Put 78 in your head and count on 5.

78… 79, 80, 81, 82, 83.

We are taking away 6 from 59. The 5 tens (50) stay the same.

We just need to do: \( 9 – 6 = 3 \).

So, 50 and 3 is 53.

This means “2 groups of 9” or “double 9”.

\( 9 + 9 = 18 \)

Starting with 45, if we take away 10, the tens digit goes down by 1.

\( 45 – 10 = 35 \).

Now we have 35. Take away another 10.

\( 35 – 10 = 25 \).

This asks: How many 5s are in 10?

Let’s count in 5s until we reach 10.

5, 10.

That is 2 groups.

We have a missing number. Something add 15 equals 21.

To find the missing part, we can do the opposite: Subtraction.

\( 21 – 15 = \square \)

Let’s count up from 15 to 21.

15… 16, 17, 18, 19, 20, 21.

That is 6 fingers.

\( \frac{1}{2} \) means “half”.

To find half of a number, we divide it by 2.

24 is made of 20 and 4.

Half of 20 is 10.

Half of 4 is 2.

10 + 2 = 12.

Start with the numbers on the right.

\( 4 + 6 = 10 \)

We write the 0 in the ones column and carry the 1 ten over to the next column.

Now add the tens, including the 1 we carried.

\( 4 + 2 + 1 = 7 \)

Always start from the right.

\( 7 – 5 = 2 \)

Now subtract the tens column.

\( 7 – 6 = 1 \)

Subtract the numbers on the right side.

\( 8 – 7 = 1 \)

Now subtract the numbers in the tens column.

\( 9 – 3 = 6 \)

This asks: How many 10s fit into 90?

Or, you can think of it as “9 tens divided by 1 ten”.

Let’s count in 10s:

10, 20, 30, 40, 50, 60, 70, 80, 90.

That is 9 tens.

Start with the right side.

\( 6 + 9 = 15 \)

Write down the 5 and carry the 1 ten.

Now add the tens, including the one we carried.

\( 3 + 5 + 1 = 9 \)

To find the missing number in an addition, we can do the opposite (subtraction).

\( 38 – 15 = \square \)

Ones: \( 8 – 5 = 3 \)

Tens: \( 3 – 1 = 2 \)

So the answer is 23.

We need to split 50 into two equal groups.

\( 50 \div 2 = \square \)

You might know that \( 25 + 25 = 50 \).

So half of 50 is 25.

Start with \( 3 – 8 \). We can’t do this!

We need to exchange a ten. We take 10 from the 30, leaving 20.

Now we have \( 13 – 8 = 5 \).

We have 2 tens left in the top number.

\( 2 – 1 = 1 \).

The numbers 44 and 51 are quite close together. It is easier to count up from 44 to 51.

Start at 44.

45, 46, 47, 48, 49, 50, 51.

That is 7 steps.

If \( 70 – \text{something} = 25 \), then \( 70 – 25 = \text{something} \).

We need to subtract 25 from 70.

We can count back in tens from 70.

70 – 10 = 60

60 – 10 = 50

Now take away the last 5: \( 50 – 5 = 45 \).