diff --git a/exercises/02_functions/functions4.rs b/exercises/02_functions/functions4.rs
index b22bffd..c1e078c 100644
--- a/exercises/02_functions/functions4.rs
+++ b/exercises/02_functions/functions4.rs
@@ -8,7 +8,7 @@ fn is_even(num: i64) -> bool {
 }
 
 // TODO: Fix the function signature.
-fn sale_price(price: i64) -> {
+fn sale_price(price: i64) -> i64 {
     if is_even(price) {
         price - 10
     } else {
diff --git a/exercises/02_functions/functions5.rs b/exercises/02_functions/functions5.rs
index 34a2ac7..a063100 100644
--- a/exercises/02_functions/functions5.rs
+++ b/exercises/02_functions/functions5.rs
@@ -1,6 +1,6 @@
 // TODO: Fix the function body without changing the signature.
 fn square(num: i32) -> i32 {
-    num * num;
+    num * num
 }
 
 fn main() {
diff --git a/exercises/03_if/if1.rs b/exercises/03_if/if1.rs
index e5a3c5a..b1a304d 100644
--- a/exercises/03_if/if1.rs
+++ b/exercises/03_if/if1.rs
@@ -4,6 +4,11 @@ fn bigger(a: i32, b: i32) -> i32 {
     // Do not use:
     // - another function call
     // - additional variables
+    if a > b {
+        a
+    } else {
+        b
+    }
 }
 
 fn main() {
diff --git a/exercises/03_if/if2.rs b/exercises/03_if/if2.rs
index ca8493c..8104487 100644
--- a/exercises/03_if/if2.rs
+++ b/exercises/03_if/if2.rs
@@ -2,8 +2,10 @@
 fn picky_eater(food: &str) -> &str {
     if food == "strawberry" {
         "Yummy!"
+    } else if food == "potato" {
+        "I guess I can eat that."
     } else {
-        1
+        "No thanks!"
     }
 }
 
diff --git a/exercises/03_if/if3.rs b/exercises/03_if/if3.rs
index 89164eb..96f81f9 100644
--- a/exercises/03_if/if3.rs
+++ b/exercises/03_if/if3.rs
@@ -3,11 +3,11 @@ fn animal_habitat(animal: &str) -> &str {
     let identifier = if animal == "crab" {
         1
     } else if animal == "gopher" {
-        2.0
+        2
     } else if animal == "snake" {
         3
     } else {
-        "Unknown"
+        0
     };
 
     // Don't change the expression below!
diff --git a/exercises/04_primitive_types/primitive_types1.rs b/exercises/04_primitive_types/primitive_types1.rs
index 84923c7..e1efa3e 100644
--- a/exercises/04_primitive_types/primitive_types1.rs
+++ b/exercises/04_primitive_types/primitive_types1.rs
@@ -8,7 +8,8 @@ fn main() {
 
     // TODO: Define a boolean variable with the name `is_evening` before the `if` statement below.
     // The value of the variable should be the negation (opposite) of `is_morning`.
-    // let …
+    let is_evening = true;
+
     if is_evening {
         println!("Good evening!");
     }
diff --git a/exercises/quizzes/quiz1.rs b/exercises/quizzes/quiz1.rs
index 04fb2aa..5395ebe 100644
--- a/exercises/quizzes/quiz1.rs
+++ b/exercises/quizzes/quiz1.rs
@@ -11,6 +11,18 @@
 // TODO: Write a function that calculates the price of an order of apples given
 // the quantity bought.
 // fn calculate_price_of_apples(???) -> ??? { ??? }
+fn calculate_price_of_apples(apples: i32) -> i32 {
+    let mut cost: i32 = 2;
+
+    if apples > 40 {
+        cost = 1;
+        cost *= apples;
+        cost
+    } else {
+        cost *= apples;
+        cost
+    }
+}
 
 fn main() {
     // You can optionally experiment here.