1. Let's start by understanding what you want to learn. Since you said "Explain as if to 8 year old," I will explain a simple math idea in a very easy way. 2. Imagine you have 3 apples and your friend gives you 2 more apples. How many apples do you have now? 3. The rule to find out how many apples you have is called addition. We write it like this: $3 + 2$ 4. Addition means putting things together. So, $3 + 2$ means you start with 3 apples and add 2 more. 5. When you count all the apples together, you get $5$ apples. 6. So, the answer to $3 + 2$ is $5$. That means you have 5 apples now! 7. Addition is one of the first math things we learn because it helps us count and understand numbers better. I hope this simple explanation helps you!