A unary operation is a type of math operation that only works on one (uni) piece of information or number. Think of it like if you only had one toy or ball to play with, instead of a bunch. Just like how you can bounce a ball or roll a toy car all by yourself, unary operations are math actions you can do on one number all by itself. Some examples of unary operations are taking the square root of a number or changing a number to a negative value. So, it's like playing with one toy all by yourself!