> For the complete documentation index, see [llms.txt](https://haskell.hpmeducation.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://haskell.hpmeducation.com/defining-functions-working-with-functions/the-infix-operator.md).

# The Infix Operator

This is a good time to introduce the **infix operator** that helps us make code a bit more readable. Normally, we apply a function by writing `<FUNCTION> <ARGUMENT1> <ARGUMENT2>`, but we could also write it using the infix operator as ``<ARGUMENT1> `<FUNCTION>` <ARGUMENT2>``. This way, we make the code more readable – for example, in the case of`res = mod sum 2`, we can instead write:

```haskell
res = sum `mod` 2 -- using the infix operator ``
```

Which then reads as "`res` is equal to `sum modulo 2`". Note that the infix operator can be used this way for **functions that take in two arguments**. For functions with more than two arguments, we would need to add parentheses to explicitly create expressions (which return another function – [currying](/types-in-haskell/function-types/curried-functions.md)):

```haskell
ghci> multiply x y z = x * y * z

ghci> (1 `multiply` 2) 3
6
```