# `if` expressions You use `if` very similarly to how you would in other languages: ```rust,editable fn main() { let mut x = 10; if x % 2 == 0 { x = x / 2; } else { x = 3 * x + 1; } } ``` In addition, you can use it as an expression. This does the same as above: ```rust,editable fn main() { let mut x = 10; x = if x % 2 == 0 { x / 2 } else { 3 * x + 1 }; } ```