ELI5: Explain Like I'm 5

Peano axioms

Imagine you have a friend called Peano. Peano loves to count things and he wants to make sure everyone can count in the same way. So, he came up with some rules for counting, called the Peano axioms.

The first axiom says that there is a starting point, and we call that starting point 0.

The second axiom says that for every number, there is a next number. So, if we have 0, then the next number is 1. And if we have 1, then the next number is 2, and so on.

The third axiom says that if two different numbers have the same next number, then they must be the same number. So, for example, if 1 has the same next number as 2, then 1 and 2 must be the same number.

The fourth axiom says that we can use induction to prove things about numbers. That might sound complicated, but it just means that if we can show that something is true for one number, and we can show that if it's true for one number then it's true for the next number, then we can say it's true for all numbers.

These Peano axioms might seem simple, but they are incredibly powerful. They allow us to define addition, subtraction, multiplication, and many other mathematical operations. And we can use these operations to solve all sorts of problems, from counting how many apples we have to figuring out how to send a rocket to space.