Point
A number is often seen as a point on a line.
Explanation
In nature, numbers are not apparent as physical entities. Anyway, you can work with them in mathematics. You should be aware that every visualisation can lead to absurd situations.
You can write the number 1 as 0.999... and then you don't know if this is the same point. If you delete the point 1 will the point 0.999... then remain or does it disappear aswell?
Representations
Sometimes, numbers are represented as beads on a string. Each bead has a number, and so you get a kind of number line. It looks like a rosary. That image can be used for simple calculations. It can also lead to confusion.
The addition 1/2 + 1/2 = 1 cannot be explained by this, allthough a child will understand it. Maybe there are large and small beads?
Advice
Use images and pictures only if they help. But always keep in mind that applies: a number is a number. That is all.