Hi number detective! We’ve got a challenge that we need your help with. Are you ready?

Let’s think about this problem:

**6 (18) 3**

How could the two outside numbers (6 and 3), make the inside number **(18)**?

We can use any of the four main number operations to make our number.

These are **addition**, **subtraction**, **multiplication** and **division**.

If we return to our problem, we can see that **6 × 3 = 18**.

So the **rule** here is that the outside numbers** multiply** together to make the inside number.

For this question, we need to work out the rule for the first set of numbers and then use that rule to work out the missing number in the next set.

Let’s look at a problem with two sets of numbers now:

**3 (7) 4, 6 ( __ ) 10**

First, let’s work out how the numbers **3** and **4** make **7**.

They **add** together to make 7.

We need to use the rule of **adding **the outside numbers for **6** and **10** to work out the missing number.

**6** and **10** add together to make **16** so the missing number is **16**.

Let’s try another one:

**12 (7) 5, 20 ( __ ) 4**

First, we need to work out how the numbers **12** and **5** can make **7**.

**12 - 5 = 7**. This means we are **taking away** the number on the right from the number on the left.

We need to apply this rule to the second pair of numbers giving us **20 - 4** which is **16**.

Pssst!! Top tip: work your way through the four main number operations until you are able to reach the number inside the brackets. |

Does that make sense?

It’s now your turn to put your skills to the test and become a number detective, hunting down those missing numbers!