In this activity, you will be asked to find the missing number in a subtraction question.

The key to this activity is calculating every answer mentally (in your head) without using pen and paper.

**Example 1**

In your head, find the missing number

**- 14 = 24**

**Answer**

Use the inverse operation (addition) in order to find the answer

**14 + 24 = 38**

**Check**

**38 - 14 = 24**

**Example 2**

**- 0.6 = 2**

**Answer **

Use the inverse operation in order to find the answer:

**2 + 0.6 = 2.6**

**Check**

**2.6 - 0.6 = 2**

**Example 3**

**34 - = 11**

**Answer **

Use the numbers you have been given to complete a subtraction sum in order to find the missing number

**34 - 11 = 23**

**Check**

**34 - 23 = 11**

**This method will make more sense when you attempt to answer some questions.**