You know how when you're doing a puzzle and you have to show your work to prove that you solved it? In math, we also need to show our work to prove that something is true. This is called a mathematical proof.
A proof is like a really long explanation that uses math to show that something is always true. When we make a statement in math, like 1+1=2, we say it's true because we can prove it using math.
To write a proof, we start by making a statement that we want to prove. For example, we might want to prove that all triangles have three sides. Then, we use math to show that this statement is always true, no matter what.
We might use things like definitions, properties, and equations to show why something is true. Sometimes we also use pictures to help us understand what's going on.
Mathematical proofs are really important because they help us understand what is true in math. They also help us solve more complicated problems and make new discoveries.