A binary operation is like two friends having a playdate! Imagine you have two toys, let's call them bear and car. Your friend also has two toys, she has a doll and a ball. When you and your friend come together to play, you can combine your toys with hers in different ways using a binary operation.
For example, you can take your bear toy and your friend's ball toy and play catch with them. That's one way of using a binary operation. Another way is to take your car toy and your friend's doll toy and make them drive around in circles.
In math, you can think of a binary operation as a rule that combines two things together to make a new thing. Just like how you combined your toys with your friend's toys to make fun new games!
For instance, you can use a binary operation on numbers, like addition, which combines two numbers to make a new number. Adding 2 and 3 together using the binary operation of addition would give you 5 as the new number.
So just like playing with toys with your friends using a binary operation, math uses a binary operation to combine and make new things!