A vertical number line resembles a thermometer. It emphasizes
that we count up in the number system. Vertical
number lines are just alternative way to look at the numbers.
This is commonly used in adding or subtracting
For example: 5 – 3
5 is the start, the sign determines whether you go down or
go up, the minus sign denotes down then so the last number denotes how many
steps you are going down where you land is the answer. The same goes with
addition but instead of down, the plus sign denotes going up.
