Kronecker's theorem is like a magic trick with numbers. Imagine you have some numbers, like 1, 2, and 3. Now, you want to do some magic with these numbers to make new numbers. How can you do that?
Kronecker's theorem says that you can use something called a polynomial to create new numbers from the old ones. A polynomial is like a special recipe that tells you how to mix the numbers together to get a new number.
For example, let's say you have the numbers 1, 2, and 3. You can use a polynomial like this: x^2 + x + 1. That means you square each number (1^2, 2^2, 3^2), add them together (1^2 + 2^2 + 3^2), then add in x (so x = 1, x = 2, and x = 3), and finally add 1 to everything. This gives you a new number.
Kronecker's theorem tells you that you can use polynomials to make any new number you want. No matter what numbers you start with, there is always a special polynomial that will create a new number for you.
This is like a magic trick because it means that you can create new numbers out of thin air, just by using some special math tricks. But it is also very important for people who study math, because it helps us understand how numbers work and how we can make new ones.