diff --git a/.rustlings-state.txt b/.rustlings-state.txt
index 8eacb71..9fe15e3 100644
--- a/.rustlings-state.txt
+++ b/.rustlings-state.txt
@@ -1,6 +1,6 @@
 DON'T EDIT THIS FILE!
 
-threads3
+clippy1
 
 intro1
 intro2
@@ -82,4 +82,9 @@ rc1
 arc1
 cow1
 threads1
-threads2
\ No newline at end of file
+threads2
+threads3
+macros1
+macros2
+macros3
+macros4
\ No newline at end of file
diff --git a/exercises/21_macros/macros1.rs b/exercises/21_macros/macros1.rs
index fb3c3ff..fb550f9 100644
--- a/exercises/21_macros/macros1.rs
+++ b/exercises/21_macros/macros1.rs
@@ -6,5 +6,5 @@ macro_rules! my_macro {
 
 fn main() {
     // TODO: Fix the macro call.
-    my_macro();
+    my_macro!();
 }
diff --git a/exercises/21_macros/macros2.rs b/exercises/21_macros/macros2.rs
index 2d9dec7..f310a0b 100644
--- a/exercises/21_macros/macros2.rs
+++ b/exercises/21_macros/macros2.rs
@@ -1,10 +1,10 @@
-fn main() {
-    my_macro!();
-}
-
 // TODO: Fix the compiler error by moving the whole definition of this macro.
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
     };
 }
+
+fn main() {
+    my_macro!();
+}
diff --git a/exercises/21_macros/macros3.rs b/exercises/21_macros/macros3.rs
index 9537494..7b2e72b 100644
--- a/exercises/21_macros/macros3.rs
+++ b/exercises/21_macros/macros3.rs
@@ -1,6 +1,7 @@
 // TODO: Fix the compiler error without taking the macro definition out of this
 // module.
 mod macros {
+    #[macro_export]
     macro_rules! my_macro {
         () => {
             println!("Check out my macro!");
diff --git a/exercises/21_macros/macros4.rs b/exercises/21_macros/macros4.rs
index 9d77f6a..3396f0d 100644
--- a/exercises/21_macros/macros4.rs
+++ b/exercises/21_macros/macros4.rs
@@ -3,7 +3,7 @@
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
-    }
+    };
     ($val:expr) => {
         println!("Look at this other macro: {}", $val);
     }
diff --git a/solutions/21_macros/macros1.rs b/solutions/21_macros/macros1.rs
index dcf2377..1b86156 100644
--- a/solutions/21_macros/macros1.rs
+++ b/solutions/21_macros/macros1.rs
@@ -1,4 +1,10 @@
+macro_rules! my_macro {
+    () => {
+        println!("Check out my macro!");
+    };
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    my_macro!();
+    //      ^
 }
diff --git a/solutions/21_macros/macros2.rs b/solutions/21_macros/macros2.rs
index dcf2377..b6fd5d2 100644
--- a/solutions/21_macros/macros2.rs
+++ b/solutions/21_macros/macros2.rs
@@ -1,4 +1,10 @@
+// Moved the macro definition to be before its call.
+macro_rules! my_macro {
+    () => {
+        println!("Check out my macro!");
+    };
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    my_macro!();
 }
diff --git a/solutions/21_macros/macros3.rs b/solutions/21_macros/macros3.rs
index dcf2377..df35be4 100644
--- a/solutions/21_macros/macros3.rs
+++ b/solutions/21_macros/macros3.rs
@@ -1,4 +1,13 @@
+// Added the attribute `macro_use` attribute.
+#[macro_use]
+mod macros {
+    macro_rules! my_macro {
+        () => {
+            println!("Check out my macro!");
+        };
+    }
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    my_macro!();
 }
diff --git a/solutions/21_macros/macros4.rs b/solutions/21_macros/macros4.rs
index dcf2377..41bcad1 100644
--- a/solutions/21_macros/macros4.rs
+++ b/solutions/21_macros/macros4.rs
@@ -1,4 +1,15 @@
+// Added semicolons to separate the macro arms.
+#[rustfmt::skip]
+macro_rules! my_macro {
+    () => {
+        println!("Check out my macro!");
+    };
+    ($val:expr) => {
+        println!("Look at this other macro: {}", $val);
+    };
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    my_macro!();
+    my_macro!(7777);
 }