To find the number halfway between $-3$ and $5$ on a number line, we can use the midpoint formula:

$\text{Midpoint} = \frac{-3 + 5}{2}$

$\text{Midpoint} = \frac{2}{2} = 1$

So, the number halfway between $-3$ and $5$ is $1$.

Would you like more details or have any other questions?

Here are 5 related questions:

1. What is the midpoint between two arbitrary numbers $a$ and $b$?
2. How do you calculate the distance between two points on a number line?
3. What number is halfway between $10$ and $20$?
4. How can you find a number one-third of the way between two numbers?
5. What is the difference between absolute value and midpoint?

Tip: The midpoint formula is essentially the average of two numbers.