Okay kiddo, let me explain what fiber means in mathematics.
Imagine you have a toy car that can move along a track. The toy car can stop at different points on the track - like at the beginning, in the middle, or at the end.
Now, think of a map that shows different cities and how to get from one city to another. There can be many different routes to get from one city to another - some routes might be long and windy, while others might be short and straight.
Both the toy car and the map have something in common with fibers in mathematics.
In math, a fiber is a set of all the things (like numbers or points) that are connected to each other in a certain way. Just like each point on the toy car track and each route on the map is connected by movement, the things in a fiber are connected by a certain relationship or rule.
For example, let's say you have a math function that takes a number as input and gives you a different number as output. The fiber of that function would be all the different input numbers that give you the same output number.
You could draw a picture of the fiber by drawing a bunch of dots - one for each possible input number - and then drawing lines to connect all the input numbers that give you the same output number.
This might seem a little bit confusing at first, but it's actually a pretty useful concept in math. By studying the fibers of different functions, mathematicians can learn more about how those functions work and how they relate to each other.
So, just like your toy car and your map have different ways of connecting things together, mathematicians use fibers to help them see how different numbers and points are connected by rules and functions.