What Is a Function in Algebra? | Khan Academy Blog

What is a function?

I’m sure that many of you have heard the term “function” in math class before. But, if you’re anything like me, you might be thinking “What the heck is a function, anyway?”

Simply put, a function is a rule that connects one set of numbers to another set of numbers. It’s kind of like a translator for math. For example, if you have the function f(x) = 2x, this rule is telling you that for any number you input (x), you multiply it by 2 to get your output (f(x)).

Functions can get a lot more complicated than that, of course. Sometimes they involve fractions, exponents, square roots, and all sorts of other funky math symbols. But at the end of the day, they’re all just rules that tell you how to take one set of numbers and turn it into another set of numbers.

So next time your math teacher asks you to find the value of a function, just remember: it’s not as scary as it sounds. It’s just like following a recipe, except instead of ending up with a tasty cake, you end up with a bunch of numbers. Yum?