diff --git a/exercises/variables/variables4.rs b/exercises/variables/variables4.rs
index 8c2ddd6d..53d09e7c 100644
--- a/exercises/variables/variables4.rs
+++ b/exercises/variables/variables4.rs
@@ -2,8 +2,8 @@
 // Execute `rustlings hint variables4` or use the `hint` watch subcommand for a hint.
 
 fn main() {
-    let mut x = 3;
+    let x = 3;
     println!("Number {}", x);
-    x = 5; // don't change this line
+    let x = 5; // don't change this line
     println!("Number {}", x);
 }