2018 Key Stage 1 Mathematics Paper 1: Arithmetic

💡 What are we doing?

We are adding 1 to the number 5. This is the same as finding the next number.

💡 Tip:

It is often easier to start with the bigger number. Start with 7 and add 2.

💡 Strategy:

Put 37 in your head and count on 5 fingers.

💡 Strategy:

Think about tens. We have 1 ten and 2 tens.

💡 Strategy:

The number 18 is made of 10 and 8.

If we take away the 8, what is left?

💡 Strategy:

We are only subtracting ones. Look at the ones digit.

We have 8 ones and we take away 4 ones.

💡 Strategy:

This means “3 groups of 10”. We can count in tens 3 times.

💡 Strategy:

Finding \( \frac{1}{2} \) (one half) is the same as sharing into 2 equal groups.

Think: “What plus what equals 6?”

💡 Strategy:

It’s easier to add the small numbers first.

💡 Strategy:

Count in 10s, 6 times.

💡 Strategy:

Count back one group of 10 from 100.

💡 Strategy:

It is hard to start at 4 and count on 81. Let’s swap them around!

💡 Strategy:

Start at 81 and count on 4.

💡 Strategy:

Multiplying by 2 is the same as doubling.

Double 7 means \( 7 + 7 \).

💡 Strategy:

We need to find what number adds to 8 to make 20.

We can count up from 8 to 20.

💡 Strategy:

Always start with the ones (the right-hand side).

4 ones + 2 ones.

💡 Strategy:

Now add the tens.

5 tens + 2 tens.

💡 Strategy:

Dividing by 2 is the same as finding half.

Share 8 into 2 equal groups.

💡 Strategy:

Start at 63 and count back 4.

💡 Strategy:

We are only changing the tens digit.

5 tens – 2 tens.

💡 Strategy:

When we add 10 to 90, we get 100.

We have 99 (which is 90 + 9).

💡 Strategy:

7 ones + 3 ones = 10 ones.

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

💡 Strategy:

6 tens + 3 tens + 1 carried ten.

💡 Strategy:

9 ones – 5 ones.

💡 Strategy:

5 tens – 1 ten.

💡 Strategy:

7 + 8 = 15.

Write 5, carry the 10.

💡 Strategy:

1 ten + 4 tens + 1 carried ten.

💡 Strategy:

To find a quarter, we can halve the number, then halve the answer.

💡 Strategy:

If \( 98 – \text{something} = 28 \), then \( 98 – 28 = \text{something} \).

Let’s do \( 98 – 28 \).

💡 Strategy:

When we divide by 10, the digits move one place to the right. The zero on the end disappears.

12 tens divided by 1 ten is 12.

💡 Strategy:

4 – 7? We can’t do it! We need to exchange 1 ten for 10 ones.

Change 70 into 60 + 10.

Now we have 14 ones.

💡 Strategy:

Now subtraction the tens.

Remember we only have 6 tens left.

6 tens – 4 tens.