This activity is about finding the missing number in adding sums.

Example

Find the value of the missing number.

Answer

We need to find the difference between the numbers 35 and 49.

We can start at 35 and count on to get to 49. This would be 14 numbers:  35 + 14 = 49

The answer is 14

We could also start at 49 and count back to 35.  This would also be 14 numbers: 49 - 35 = 14

Both methods are correct and give us the same answer of 14. Which method works best for you?