diff --git a/variables/variables1.rs b/variables/variables1.rs
index e0ad5de..4be88a3 100644
--- a/variables/variables1.rs
+++ b/variables/variables1.rs
@@ -1,7 +1,7 @@
 // Make me compile! Scroll down for hints :)
 
 fn main() {
-    x = 5;
+    let x = 5;
     println!("x has the value {}", x);
 }
 
diff --git a/variables/variables2.rs b/variables/variables2.rs
index ca02438..1cb2542 100644
--- a/variables/variables2.rs
+++ b/variables/variables2.rs
@@ -1,7 +1,7 @@
 // Make me compile! Scroll down for hints :)
 
 fn main() {
-    let x;
+    let x: i32 = 30;
     if x == 10 {
         println!("Ten!");
     } else {
diff --git a/variables/variables3.rs b/variables/variables3.rs
index ec55a95..0be8cb8 100644
--- a/variables/variables3.rs
+++ b/variables/variables3.rs
@@ -1,7 +1,7 @@
 // Make me compile! Scroll down for hints :)
 
 fn main() {
-    let x = 3;
+    let mut x = 3;
     println!("Number {}", x);
     x = 5;
     println!("Number {}", x);
diff --git a/variables/variables4.rs b/variables/variables4.rs
index 3f7f937..cce7706 100644
--- a/variables/variables4.rs
+++ b/variables/variables4.rs
@@ -1,7 +1,7 @@
 // Make me compile! Scroll down for hints :)
 
 fn main() {
-    let x: i32;
+    let x: i32 = 37;
     println!("Number {}", x);
 }