You might find a number line useful when answering questions involving negative numbers.

When you add a positive number, go up the number line.

When you subtract a positive number, go down the number line.

### Example 1

$6 - 3 = 6 + (\,- \,3) = 3$

### Example 2

$4 - 5 = 4 + (\,-\,5) = - 1$

### Example 3

$-\,2 + 5 = 3$

Now try these questions and remember the number line!

Question

$4 - 9$

$4 - 9 = 4 + (\,-\,9) = -\,5$

Question

$3 - 10$

$3 - 10 = 3 + (\,-\,10) = -\,7$

Question

$- 9 + 12$

$- 9 + 12 = 3$