The image depicts a number line with a blue arrow starting at 1 and ending at 3, along with a mathematical expression represented by blank spaces for the user to fill in. Here's what the image asks:

• The arrow on the number line starts at 1 and moves to 3, indicating a movement of 2 units to the right.
• The expression below seems to involve an addition operation, and the number line helps to visualize the addition.

The blanks represent the numbers involved in the addition: 1 + 2 = 3.

So, the filled-in equation would be: $1 + 2 = 3$

Would you like more detailed information or have any questions?

Here are five related questions to explore this concept further:

1. What does moving to the right on a number line represent in addition?
2. Can you explain how subtraction would look on the number line?
3. What is the significance of the starting and ending points on a number line?
4. How can you use a number line for negative numbers in addition?
5. How would the equation change if the arrow moved to the left?

Tip: Always align your addition and subtraction problems with a number line for a clearer understanding of movement between numbers.