Answer:
4 units
Explanation:
Number lines are linear representations of length or some other unit.
Number Lines
Number lines are always straight lines that only have one dimension. This means that there is only one axis or line that has values. As seen in the picture, number lines are usually drawn horizontally and marked with numbers to visually represent data.
Line of QR
The question asks for the units of QR. This notation represents the line between the 2 points Q and R. So, to find the length of the line we can simply count the distance between the two points. Between the values of -3 and 1, there are 4 units. So, the line has a length of 4 units.
We can also find the length by subtracting the two numbers.