The diagram shows a vertical number line with an arrow starting at 8 and pointing downwards to 4. Then, another arrow extends from 4 down to -4.

To write an equation for this, let's break it down into two steps:

1. The first arrow represents subtraction, moving from 8 to 4. This is a drop of 4 units, so: $8 - 4 = 4$

2. The second arrow represents moving from 4 to -4, which is a drop of 8 units, so: $4 - 8 = -4$

Combining both steps into a single equation: $8 - 4 - 8 = -4$

Alternatively, if you wanted to write this using addition: $8 + (-4) + (-8) = -4$

Would you like more details on any part of this? Here are some related questions:

1. How do you convert subtraction to addition with negative numbers?
2. What are the rules for adding and subtracting integers?
3. How can you represent similar movements on a horizontal number line?
4. How does this apply to real-life scenarios like temperature changes?
5. Can you always combine several steps into one equation?

Tip: When adding or subtracting integers, always pay attention to the direction (positive or negative) and magnitude of movement on the number line.