diff --git a/exercises/enums/enums1.rs b/exercises/enums/enums1.rs
index 25525b25..f08d21b8 100644
--- a/exercises/enums/enums1.rs
+++ b/exercises/enums/enums1.rs
@@ -2,11 +2,15 @@
 //
 // No hints this time! ;)
 
-// I AM NOT DONE
+
 
 #[derive(Debug)]
 enum Message {
     // TODO: define a few types of messages as used below
+    Quit,
+    Echo,
+    Move,
+    ChangeColor,
 }
 
 fn main() {
diff --git a/exercises/enums/enums2.rs b/exercises/enums/enums2.rs
index df93fe0f..7a93b202 100644
--- a/exercises/enums/enums2.rs
+++ b/exercises/enums/enums2.rs
@@ -3,11 +3,15 @@
 // Execute `rustlings hint enums2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 #[derive(Debug)]
 enum Message {
     // TODO: define the different variants used below
+    Move{x: i32, y: i32},
+    Echo(String),
+    ChangeColor(u8, u8, u8),
+    Quit,
 }
 
 impl Message {
diff --git a/exercises/enums/enums3.rs b/exercises/enums/enums3.rs
index 5d284417..63290b6d 100644
--- a/exercises/enums/enums3.rs
+++ b/exercises/enums/enums3.rs
@@ -5,10 +5,14 @@
 // Execute `rustlings hint enums3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 enum Message {
     // TODO: implement the message variant types based on their usage below
+    ChangeColor(u8, u8, u8),
+    Echo(String),
+    Move(Point),
+    Quit,
 }
 
 struct Point {
@@ -43,6 +47,12 @@ impl State {
         // variants
         // Remember: When passing a tuple as a function argument, you'll need
         // extra parentheses: fn function((t, u, p, l, e))
+        match message {
+            Message::ChangeColor(r, g, b) => self.change_color((r, g, b)),
+            Message::Echo(s) => self.echo(s),
+            Message::Move(p) => self.move_position(p),
+            Message::Quit => self.quit(),
+        }
     }
 }
 
diff --git a/exercises/error_handling/errors1.rs b/exercises/error_handling/errors1.rs
index 13d2724c..595dc51d 100644
--- a/exercises/error_handling/errors1.rs
+++ b/exercises/error_handling/errors1.rs
@@ -9,14 +9,12 @@
 // Execute `rustlings hint errors1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
-pub fn generate_nametag_text(name: String) -> Option<String> {
+pub fn generate_nametag_text(name: String) -> Result<String, String> {
     if name.is_empty() {
         // Empty names aren't allowed.
-        None
+        Err("`name` was empty; it must be nonempty.".into())
     } else {
-        Some(format!("Hi! My name is {}", name))
+        Ok(format!("Hi! My name is {}", name))
     }
 }
 
diff --git a/exercises/error_handling/errors2.rs b/exercises/error_handling/errors2.rs
index d86f326d..372f10a9 100644
--- a/exercises/error_handling/errors2.rs
+++ b/exercises/error_handling/errors2.rs
@@ -19,14 +19,16 @@
 // Execute `rustlings hint errors2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
     let processing_fee = 1;
     let cost_per_item = 5;
-    let qty = item_quantity.parse::<i32>();
+    // let qty = item_quantity.parse::<i32>()?;
+    let qty = match item_quantity.parse::<i32>() {
+        Ok(total) => total,
+        Err(e) => return Err(e),
+    };
 
     Ok(qty * cost_per_item + processing_fee)
 }
diff --git a/exercises/error_handling/errors3.rs b/exercises/error_handling/errors3.rs
index d42d3b17..8222ec43 100644
--- a/exercises/error_handling/errors3.rs
+++ b/exercises/error_handling/errors3.rs
@@ -7,11 +7,9 @@
 // Execute `rustlings hint errors3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
-fn main() {
+fn main() -> Result<(), ParseIntError> {
     let mut tokens = 100;
     let pretend_user_input = "8";
 
@@ -23,6 +21,7 @@ fn main() {
         tokens -= cost;
         println!("You now have {} tokens.", tokens);
     }
+    Ok(())
 }
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
diff --git a/exercises/error_handling/errors4.rs b/exercises/error_handling/errors4.rs
index e04bff77..d0e97a8c 100644
--- a/exercises/error_handling/errors4.rs
+++ b/exercises/error_handling/errors4.rs
@@ -3,8 +3,6 @@
 // Execute `rustlings hint errors4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
 
@@ -17,7 +15,19 @@ enum CreationError {
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
         // Hmm...? Why is this only returning an Ok value?
-        Ok(PositiveNonzeroInteger(value as u64))
+        // if value > 0 {
+        //     Ok(PositiveNonzeroInteger(value as u64))
+        // } else if value == 0 {
+        //     Err(CreationError::Zero)
+        // } else {
+        //     Err(CreationError::Negative)
+        // }
+        use std::cmp::Ordering;
+        match value.cmp(&0) {
+            Ordering::Greater => Ok(PositiveNonzeroInteger(value as u64)),
+            Ordering::Equal => Err(CreationError::Zero),
+            Ordering::Less =>Err(CreationError::Negative),
+        }
     }
 }
 
diff --git a/exercises/error_handling/errors5.rs b/exercises/error_handling/errors5.rs
index 92461a7e..797a60d4 100644
--- a/exercises/error_handling/errors5.rs
+++ b/exercises/error_handling/errors5.rs
@@ -22,14 +22,12 @@
 // Execute `rustlings hint errors5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::error;
 use std::fmt;
 use std::num::ParseIntError;
 
 // TODO: update the return type of `main()` to make this compile.
-fn main() -> Result<(), Box<dyn ???>> {
+fn main() -> Result<(), Box<dyn error::Error>> {
     let pretend_user_input = "42";
     let x: i64 = pretend_user_input.parse()?;
     println!("output={:?}", PositiveNonzeroInteger::new(x)?);
diff --git a/exercises/error_handling/errors6.rs b/exercises/error_handling/errors6.rs
index aaf0948e..902b5114 100644
--- a/exercises/error_handling/errors6.rs
+++ b/exercises/error_handling/errors6.rs
@@ -52,6 +52,7 @@ impl PositiveNonzeroInteger {
             x if x < 0 => Err(CreationError::Negative),
             x if x == 0 => Err(CreationError::Zero),
             x => Ok(PositiveNonzeroInteger(x as u64)),
+            Err(e) => Err(ParsePosNonzeroError::from_creation(e)),
         }
     }
 }
diff --git a/exercises/functions/functions1.rs b/exercises/functions/functions1.rs
index 40ed9a07..2cfda13d 100644
--- a/exercises/functions/functions1.rs
+++ b/exercises/functions/functions1.rs
@@ -3,7 +3,8 @@
 // Execute `rustlings hint functions1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
+fn call_me() {}
 
 fn main() {
     call_me();
diff --git a/exercises/functions/functions2.rs b/exercises/functions/functions2.rs
index 5154f34d..da4f2b14 100644
--- a/exercises/functions/functions2.rs
+++ b/exercises/functions/functions2.rs
@@ -3,13 +3,12 @@
 // Execute `rustlings hint functions2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {
     call_me(3);
 }
 
-fn call_me(num:) {
+fn call_me(num: u32) {
     for i in 0..num {
         println!("Ring! Call number {}", i + 1);
     }
diff --git a/exercises/functions/functions3.rs b/exercises/functions/functions3.rs
index 74f44d6d..0a01731c 100644
--- a/exercises/functions/functions3.rs
+++ b/exercises/functions/functions3.rs
@@ -3,10 +3,9 @@
 // Execute `rustlings hint functions3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {
-    call_me();
+    call_me(3);
 }
 
 fn call_me(num: u32) {
diff --git a/exercises/functions/functions4.rs b/exercises/functions/functions4.rs
index 77c4b2aa..96891ce2 100644
--- a/exercises/functions/functions4.rs
+++ b/exercises/functions/functions4.rs
@@ -8,14 +8,13 @@
 // Execute `rustlings hint functions4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {
     let original_price = 51;
     println!("Your sale price is {}", sale_price(original_price));
 }
 
-fn sale_price(price: i32) -> {
+fn sale_price(price: i32) -> i32 {
     if is_even(price) {
         price - 10
     } else {
diff --git a/exercises/functions/functions5.rs b/exercises/functions/functions5.rs
index f1b63f48..a9dd1b57 100644
--- a/exercises/functions/functions5.rs
+++ b/exercises/functions/functions5.rs
@@ -3,7 +3,6 @@
 // Execute `rustlings hint functions5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {
     let answer = square(3);
@@ -11,5 +10,5 @@ fn main() {
 }
 
 fn square(num: i32) -> i32 {
-    num * num;
+    num * num
 }
diff --git a/exercises/hashmaps/hashmaps1.rs b/exercises/hashmaps/hashmaps1.rs
index 80829eaa..1c9a2462 100644
--- a/exercises/hashmaps/hashmaps1.rs
+++ b/exercises/hashmaps/hashmaps1.rs
@@ -11,17 +11,19 @@
 // Execute `rustlings hint hashmaps1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 use std::collections::HashMap;
 
 fn fruit_basket() -> HashMap<String, u32> {
-    let mut basket = // TODO: declare your hash map here.
+    let mut basket = HashMap::<String, u32>::new();// TODO: declare your hash map here.
 
     // Two bananas are already given for you :)
     basket.insert(String::from("banana"), 2);
 
     // TODO: Put more fruits in your basket here.
+    basket.insert(String::from("apple"), 2);
+    basket.insert(String::from("orange"), 2);
 
     basket
 }
diff --git a/exercises/hashmaps/hashmaps2.rs b/exercises/hashmaps/hashmaps2.rs
index a5925690..a80acd5d 100644
--- a/exercises/hashmaps/hashmaps2.rs
+++ b/exercises/hashmaps/hashmaps2.rs
@@ -14,7 +14,7 @@
 // Execute `rustlings hint hashmaps2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 use std::collections::HashMap;
 
@@ -40,6 +40,14 @@ fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
         // TODO: Insert new fruits if they are not already present in the
         // basket. Note that you are not allowed to put any type of fruit that's
         // already present!
+        match fruit {
+            Fruit::Apple => {},
+            Fruit::Mango => {},
+            Fruit::Lychee => {},
+            Fruit::Banana | Fruit::Pineapple => {
+                basket.entry(fruit).or_insert(1);
+            }
+        }
     }
 }
 
diff --git a/exercises/hashmaps/hashmaps3.rs b/exercises/hashmaps/hashmaps3.rs
index 08e977c3..8cc7c706 100644
--- a/exercises/hashmaps/hashmaps3.rs
+++ b/exercises/hashmaps/hashmaps3.rs
@@ -14,7 +14,7 @@
 // Execute `rustlings hint hashmaps3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 use std::collections::HashMap;
 
@@ -39,6 +39,14 @@ fn build_scores_table(results: String) -> HashMap<String, Team> {
         // will be the number of goals conceded from team_2, and similarly
         // goals scored by team_2 will be the number of goals conceded by
         // team_1.
+        let n = scores.entry(team_1_name).or_insert(Team{goals_conceded:0, goals_scored: 0});
+        n.goals_scored += team_1_score;
+        n.goals_conceded += team_2_score;
+
+        let n = scores.entry(team_2_name).or_insert(Team{goals_conceded:0, goals_scored: 0});
+        n.goals_scored += team_2_score;
+        n.goals_conceded += team_1_score;
+
     }
     scores
 }
diff --git a/exercises/if/if1.rs b/exercises/if/if1.rs
index d8108a0f..308003b1 100644
--- a/exercises/if/if1.rs
+++ b/exercises/if/if1.rs
@@ -2,13 +2,17 @@
 //
 // Execute `rustlings hint if1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
 
 pub fn bigger(a: i32, b: i32) -> i32 {
     // Complete this function to return the bigger number!
     // Do not use:
     // - another function call
     // - additional variables
+    if a > b {
+        a
+    } else {
+        b
+    }
 }
 
 // Don't mind this for now :)
diff --git a/exercises/if/if2.rs b/exercises/if/if2.rs
index f512f13f..40c07802 100644
--- a/exercises/if/if2.rs
+++ b/exercises/if/if2.rs
@@ -5,13 +5,14 @@
 //
 // Execute `rustlings hint if2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
 
 pub fn foo_if_fizz(fizzish: &str) -> &str {
     if fizzish == "fizz" {
         "foo"
+    } else if fizzish == "fuzz" {
+        "bar"
     } else {
-        1
+        "baz"
     }
 }
 
diff --git a/exercises/if/if3.rs b/exercises/if/if3.rs
index 73a7025b..ea3a1b28 100644
--- a/exercises/if/if3.rs
+++ b/exercises/if/if3.rs
@@ -2,17 +2,16 @@
 //
 // Execute `rustlings hint if3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
 
 pub fn animal_habitat(animal: &str) -> &'static str {
     let identifier = if animal == "crab" {
         1
     } else if animal == "gopher" {
-        2.0
+        2
     } else if animal == "snake" {
         3
     } else {
-        "Unknown"
+        0
     };
 
     // DO NOT CHANGE THIS STATEMENT BELOW
diff --git a/exercises/intro/intro1.rs b/exercises/intro/intro1.rs
index 37fa0112..143c0a3d 100644
--- a/exercises/intro/intro1.rs
+++ b/exercises/intro/intro1.rs
@@ -13,8 +13,6 @@
 // Execute `rustlings hint intro1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
     println!("Hello and");
     println!(r#"       welcome to...                      "#);
diff --git a/exercises/intro/intro2.rs b/exercises/intro/intro2.rs
index 990b20f0..bf6a776f 100644
--- a/exercises/intro/intro2.rs
+++ b/exercises/intro/intro2.rs
@@ -5,8 +5,6 @@
 // Execute `rustlings hint intro2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
-    println!("Hello {}!");
+    println!("Hello {}!", String::from("world"));
 }
diff --git a/exercises/modules/modules1.rs b/exercises/modules/modules1.rs
index 9eb5a48b..94308b5c 100644
--- a/exercises/modules/modules1.rs
+++ b/exercises/modules/modules1.rs
@@ -3,7 +3,7 @@
 // Execute `rustlings hint modules1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 mod sausage_factory {
     // Don't let anybody outside of this module see this!
@@ -11,7 +11,7 @@ mod sausage_factory {
         String::from("Ginger")
     }
 
-    fn make_sausage() {
+    pub fn make_sausage() {
         get_secret_recipe();
         println!("sausage!");
     }
diff --git a/exercises/modules/modules2.rs b/exercises/modules/modules2.rs
index 04154543..a16b8c99 100644
--- a/exercises/modules/modules2.rs
+++ b/exercises/modules/modules2.rs
@@ -7,12 +7,12 @@
 // Execute `rustlings hint modules2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 mod delicious_snacks {
     // TODO: Fix these use statements
-    use self::fruits::PEAR as ???
-    use self::veggies::CUCUMBER as ???
+    pub use self::fruits::PEAR as fruit;
+    pub use self::veggies::CUCUMBER as veggie;
 
     mod fruits {
         pub const PEAR: &'static str = "Pear";
diff --git a/exercises/modules/modules3.rs b/exercises/modules/modules3.rs
index f2bb0503..0e19dc5f 100644
--- a/exercises/modules/modules3.rs
+++ b/exercises/modules/modules3.rs
@@ -8,10 +8,11 @@
 // Execute `rustlings hint modules3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 // TODO: Complete this use statement
-use ???
+use std::time::UNIX_EPOCH as UNIX_EPOCH;
+use std::time::SystemTime as SystemTime;
 
 fn main() {
     match SystemTime::now().duration_since(UNIX_EPOCH) {
diff --git a/exercises/move_semantics/move_semantics1.rs b/exercises/move_semantics/move_semantics1.rs
index 710d20d8..eac7d31b 100644
--- a/exercises/move_semantics/move_semantics1.rs
+++ b/exercises/move_semantics/move_semantics1.rs
@@ -3,12 +3,10 @@
 // Execute `rustlings hint move_semantics1` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let vec0 = Vec::new();
 
-    let vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec(vec0);
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 
diff --git a/exercises/move_semantics/move_semantics2.rs b/exercises/move_semantics/move_semantics2.rs
index 72d37fa4..c7b0d9f3 100644
--- a/exercises/move_semantics/move_semantics2.rs
+++ b/exercises/move_semantics/move_semantics2.rs
@@ -7,12 +7,10 @@
 // Execute `rustlings hint move_semantics2` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let vec0 = Vec::new();
 
-    let mut vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec(vec0.clone());
 
     println!("{} has length {}, with contents: `{:?}`", "vec0", vec0.len(), vec0);
 
diff --git a/exercises/move_semantics/move_semantics3.rs b/exercises/move_semantics/move_semantics3.rs
index ea214934..7da54e38 100644
--- a/exercises/move_semantics/move_semantics3.rs
+++ b/exercises/move_semantics/move_semantics3.rs
@@ -6,8 +6,6 @@
 // Execute `rustlings hint move_semantics3` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let vec0 = Vec::new();
 
@@ -20,7 +18,7 @@ fn main() {
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+fn fill_vec(mut vec: Vec<i32>) -> Vec<i32> {
     vec.push(22);
     vec.push(44);
     vec.push(66);
diff --git a/exercises/move_semantics/move_semantics4.rs b/exercises/move_semantics/move_semantics4.rs
index 75a3b6bd..045ab569 100644
--- a/exercises/move_semantics/move_semantics4.rs
+++ b/exercises/move_semantics/move_semantics4.rs
@@ -7,12 +7,8 @@
 // Execute `rustlings hint move_semantics4` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let vec0 = Vec::new();
-
-    let mut vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec();
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 
@@ -23,7 +19,7 @@ fn main() {
 
 // `fill_vec()` no longer takes `vec: Vec<i32>` as argument
 fn fill_vec() -> Vec<i32> {
-    let mut vec = vec;
+    let mut vec = vec![];
 
     vec.push(22);
     vec.push(44);
diff --git a/exercises/move_semantics/move_semantics5.rs b/exercises/move_semantics/move_semantics5.rs
index 68db09eb..bf373822 100644
--- a/exercises/move_semantics/move_semantics5.rs
+++ b/exercises/move_semantics/move_semantics5.rs
@@ -6,13 +6,11 @@
 // Execute `rustlings hint move_semantics5` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let mut x = 100;
     let y = &mut x;
-    let z = &mut x;
     *y += 100;
+    let z = &mut x;
     *z += 1000;
     assert_eq!(x, 1200);
 }
diff --git a/exercises/move_semantics/move_semantics6.rs b/exercises/move_semantics/move_semantics6.rs
index cace4ca6..f00dab19 100644
--- a/exercises/move_semantics/move_semantics6.rs
+++ b/exercises/move_semantics/move_semantics6.rs
@@ -5,24 +5,22 @@
 // Execute `rustlings hint move_semantics6` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let data = "Rust is great!".to_string();
 
-    get_char(data);
+    get_char(&data);
 
-    string_uppercase(&data);
+    string_uppercase(data);
 }
 
 // Should not take ownership
-fn get_char(data: String) -> char {
+fn get_char(data: &String) -> char {
     data.chars().last().unwrap()
 }
 
 // Should take ownership
-fn string_uppercase(mut data: &String) {
-    data = &data.to_uppercase();
+fn string_uppercase(mut data: String) {
+    data = data.to_uppercase();
 
     println!("{}", data);
 }
diff --git a/exercises/options/options1.rs b/exercises/options/options1.rs
index e131b48b..5bfe3fb6 100644
--- a/exercises/options/options1.rs
+++ b/exercises/options/options1.rs
@@ -3,7 +3,6 @@
 // Execute `rustlings hint options1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 // This function returns how much icecream there is left in the fridge.
 // If it's before 10PM, there's 5 pieces left. At 10PM, someone eats them
@@ -13,7 +12,11 @@ fn maybe_icecream(time_of_day: u16) -> Option<u16> {
     // value of 0 The Option output should gracefully handle cases where
     // time_of_day > 23.
     // TODO: Complete the function body - remember to return an Option!
-    ???
+    match time_of_day {
+        0..=21 => Some(5),
+        22..=24 => Some(0),
+        _ => None,
+    }
 }
 
 #[cfg(test)]
@@ -34,6 +37,6 @@ mod tests {
         // TODO: Fix this test. How do you get at the value contained in the
         // Option?
         let icecreams = maybe_icecream(12);
-        assert_eq!(icecreams, 5);
+        assert_eq!(icecreams.unwrap_or(0), 5);
     }
 }
diff --git a/exercises/options/options2.rs b/exercises/options/options2.rs
index 4d998e7d..0575d122 100644
--- a/exercises/options/options2.rs
+++ b/exercises/options/options2.rs
@@ -3,7 +3,6 @@
 // Execute `rustlings hint options2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 #[cfg(test)]
 mod tests {
@@ -13,7 +12,7 @@ mod tests {
         let optional_target = Some(target);
 
         // TODO: Make this an if let statement whose value is "Some" type
-        word = optional_target {
+        if let Some(word) = optional_target {
             assert_eq!(word, target);
         }
     }
@@ -21,7 +20,7 @@ mod tests {
     #[test]
     fn layered_option() {
         let range = 10;
-        let mut optional_integers: Vec<Option<i8>> = vec![None];
+        let mut optional_integers: Vec<Option<i8>> = vec![];
 
         for i in 1..(range + 1) {
             optional_integers.push(Some(i));
@@ -32,7 +31,7 @@ mod tests {
         // TODO: make this a while let statement - remember that vector.pop also
         // adds another layer of Option<T>. You can stack `Option<T>`s into
         // while let and if let.
-        integer = optional_integers.pop() {
+        while let Some(integer) = optional_integers.pop().flatten() {
             assert_eq!(integer, cursor);
             cursor -= 1;
         }
diff --git a/exercises/options/options3.rs b/exercises/options/options3.rs
index 23c15eab..76664fff 100644
--- a/exercises/options/options3.rs
+++ b/exercises/options/options3.rs
@@ -3,7 +3,6 @@
 // Execute `rustlings hint options3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 struct Point {
     x: i32,
@@ -14,7 +13,7 @@ fn main() {
     let y: Option<Point> = Some(Point { x: 100, y: 200 });
 
     match y {
-        Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),
+        Some(ref p) => println!("Co-ordinates are {},{} ", p.x, p.y),
         _ => panic!("no match!"),
     }
     y; // Fix without deleting this line.
diff --git a/exercises/primitive_types/primitive_types1.rs b/exercises/primitive_types/primitive_types1.rs
index e1cf52a2..b2271abc 100644
--- a/exercises/primitive_types/primitive_types1.rs
+++ b/exercises/primitive_types/primitive_types1.rs
@@ -6,7 +6,6 @@
 // Execute `rustlings hint primitive_types1` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
 
 fn main() {
     // Booleans (`bool`)
@@ -16,7 +15,7 @@ fn main() {
         println!("Good morning!");
     }
 
-    let // Finish the rest of this line like the example! Or make it be false!
+    let is_evening = true; // Finish the rest of this line like the example! Or make it be false!
     if is_evening {
         println!("Good evening!");
     }
diff --git a/exercises/primitive_types/primitive_types2.rs b/exercises/primitive_types/primitive_types2.rs
index fcc9705a..6acd8adb 100644
--- a/exercises/primitive_types/primitive_types2.rs
+++ b/exercises/primitive_types/primitive_types2.rs
@@ -6,7 +6,6 @@
 // Execute `rustlings hint primitive_types2` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
 
 fn main() {
     // Characters (`char`)
@@ -22,7 +21,7 @@ fn main() {
         println!("Neither alphabetic nor numeric!");
     }
 
-    let // Finish this line like the example! What's your favorite character?
+    let your_character = 'c';// Finish this line like the example! What's your favorite character?
     // Try a letter, try a number, try a special character, try a character
     // from a different language than your own, try an emoji!
     if your_character.is_alphabetic() {
diff --git a/exercises/primitive_types/primitive_types3.rs b/exercises/primitive_types/primitive_types3.rs
index 06a7a621..d8ac3c43 100644
--- a/exercises/primitive_types/primitive_types3.rs
+++ b/exercises/primitive_types/primitive_types3.rs
@@ -5,10 +5,8 @@
 // Execute `rustlings hint primitive_types3` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let a = ???
+    let a: [char; 100]= ['a'; 100];
 
     if a.len() >= 100 {
         println!("Wow, that's a big array!");
diff --git a/exercises/primitive_types/primitive_types4.rs b/exercises/primitive_types/primitive_types4.rs
index d44d8776..be863098 100644
--- a/exercises/primitive_types/primitive_types4.rs
+++ b/exercises/primitive_types/primitive_types4.rs
@@ -5,13 +5,11 @@
 // Execute `rustlings hint primitive_types4` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 #[test]
 fn slice_out_of_array() {
     let a = [1, 2, 3, 4, 5];
 
-    let nice_slice = ???
+    let nice_slice = &a[1..4];
 
     assert_eq!([2, 3, 4], nice_slice)
 }
diff --git a/exercises/primitive_types/primitive_types5.rs b/exercises/primitive_types/primitive_types5.rs
index f646986e..701904c4 100644
--- a/exercises/primitive_types/primitive_types5.rs
+++ b/exercises/primitive_types/primitive_types5.rs
@@ -5,11 +5,10 @@
 // Execute `rustlings hint primitive_types5` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
 
 fn main() {
     let cat = ("Furry McFurson", 3.5);
-    let /* your pattern here */ = cat;
+    let (name, age)= cat;
 
     println!("{} is {} years old.", name, age);
 }
diff --git a/exercises/primitive_types/primitive_types6.rs b/exercises/primitive_types/primitive_types6.rs
index 07cc46c6..0ed7cfd2 100644
--- a/exercises/primitive_types/primitive_types6.rs
+++ b/exercises/primitive_types/primitive_types6.rs
@@ -6,13 +6,11 @@
 // Execute `rustlings hint primitive_types6` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 #[test]
 fn indexing_tuple() {
     let numbers = (1, 2, 3);
     // Replace below ??? with the tuple indexing syntax.
-    let second = ???;
+    let second = numbers.1;
 
     assert_eq!(2, second,
         "This is not the 2nd number in the tuple!")
diff --git a/exercises/quiz1.rs b/exercises/quiz1.rs
index a9904b8b..3c0d7a75 100644
--- a/exercises/quiz1.rs
+++ b/exercises/quiz1.rs
@@ -13,10 +13,15 @@
 //
 // No hints this time ;)
 
-// I AM NOT DONE
 
 // Put your function here!
-// fn calculate_price_of_apples {
+fn calculate_price_of_apples(x: i32) -> i32 {
+    if x <= 40 {
+        x * 2
+    } else {
+        x
+    }
+}
 
 // Don't modify this function!
 #[test]
diff --git a/exercises/quiz2.rs b/exercises/quiz2.rs
index 29925caf..4a63d3f9 100644
--- a/exercises/quiz2.rs
+++ b/exercises/quiz2.rs
@@ -20,7 +20,7 @@
 //
 // No hints this time!
 
-// I AM NOT DONE
+
 
 pub enum Command {
     Uppercase,
@@ -32,11 +32,22 @@ mod my_module {
     use super::Command;
 
     // TODO: Complete the function signature!
-    pub fn transformer(input: ???) -> ??? {
+    pub fn transformer(input: Vec<(String, Command)>) -> Vec<String> {
         // TODO: Complete the output declaration!
-        let mut output: ??? = vec![];
+        let mut output: Vec<String> = vec![];
         for (string, command) in input.iter() {
             // TODO: Complete the function body. You can do it!
+            match command {
+                Command::Uppercase => {
+                    output.push(string.to_uppercase())
+                },
+                Command::Trim => {
+                    output.push(string.trim().to_string());
+                },
+                Command::Append(n) => {
+                    output.push(string.to_owned() + &"bar".repeat(*n));
+                }
+            }
         }
         output
     }
@@ -45,7 +56,7 @@ mod my_module {
 #[cfg(test)]
 mod tests {
     // TODO: What do we need to import to have `transformer` in scope?
-    use ???;
+    use crate::my_module::transformer as transformer;
     use super::Command;
 
     #[test]
diff --git a/exercises/strings/strings1.rs b/exercises/strings/strings1.rs
index f50e1fa9..ea870dcb 100644
--- a/exercises/strings/strings1.rs
+++ b/exercises/strings/strings1.rs
@@ -5,7 +5,7 @@
 // Execute `rustlings hint strings1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 fn main() {
     let answer = current_favorite_color();
@@ -13,5 +13,5 @@ fn main() {
 }
 
 fn current_favorite_color() -> String {
-    "blue"
+    String::from("blue")
 }
diff --git a/exercises/strings/strings2.rs b/exercises/strings/strings2.rs
index 4d95d16a..81cb0bac 100644
--- a/exercises/strings/strings2.rs
+++ b/exercises/strings/strings2.rs
@@ -5,11 +5,11 @@
 // Execute `rustlings hint strings2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 fn main() {
     let word = String::from("green"); // Try not changing this line :)
-    if is_a_color_word(word) {
+    if is_a_color_word(&word) {
         println!("That is a color word I know!");
     } else {
         println!("That is not a color word I know.");
diff --git a/exercises/strings/strings3.rs b/exercises/strings/strings3.rs
index b29f9325..5709bd39 100644
--- a/exercises/strings/strings3.rs
+++ b/exercises/strings/strings3.rs
@@ -3,21 +3,21 @@
 // Execute `rustlings hint strings3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 fn trim_me(input: &str) -> String {
     // TODO: Remove whitespace from both ends of a string!
-    ???
+    input.to_string().trim_start().trim_end().to_string()
 }
 
 fn compose_me(input: &str) -> String {
     // TODO: Add " world!" to the string! There's multiple ways to do this!
-    ???
+    input.to_string() + &String::from(" world!")
 }
 
 fn replace_me(input: &str) -> String {
     // TODO: Replace "cars" in the string with "balloons"!
-    ???
+    input.to_string().replace("cars", "balloons")
 }
 
 #[cfg(test)]
diff --git a/exercises/strings/strings4.rs b/exercises/strings/strings4.rs
index e8c54acc..04c51428 100644
--- a/exercises/strings/strings4.rs
+++ b/exercises/strings/strings4.rs
@@ -7,7 +7,7 @@
 //
 // No hints this time!
 
-// I AM NOT DONE
+
 
 fn string_slice(arg: &str) {
     println!("{}", arg);
@@ -17,14 +17,14 @@ fn string(arg: String) {
 }
 
 fn main() {
-    ???("blue");
-    ???("red".to_string());
-    ???(String::from("hi"));
-    ???("rust is fun!".to_owned());
-    ???("nice weather".into());
-    ???(format!("Interpolation {}", "Station"));
-    ???(&String::from("abc")[0..1]);
-    ???("  hello there ".trim());
-    ???("Happy Monday!".to_string().replace("Mon", "Tues"));
-    ???("mY sHiFt KeY iS sTiCkY".to_lowercase());
+    string_slice("blue");
+    string("red".to_string());
+    string(String::from("hi"));
+    string("rust is fun!".to_owned());
+    string("nice weather".into());
+    string(format!("Interpolation {}", "Station"));
+    string_slice(&String::from("abc")[0..1]);
+    string_slice("  hello there ".trim());
+    string("Happy Monday!".to_string().replace("Mon", "Tues"));
+    string("mY sHiFt KeY iS sTiCkY".to_lowercase());
 }
diff --git a/exercises/structs/structs1.rs b/exercises/structs/structs1.rs
index 5fa5821c..d5024ea6 100644
--- a/exercises/structs/structs1.rs
+++ b/exercises/structs/structs1.rs
@@ -5,13 +5,14 @@
 // Execute `rustlings hint structs1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 struct ColorClassicStruct {
     // TODO: Something goes here
+    red: u8,
+    green: u8,
+    blue: u8,
 }
 
-struct ColorTupleStruct(/* TODO: Something goes here */);
+struct ColorTupleStruct(u8, u8, u8);
 
 #[derive(Debug)]
 struct UnitLikeStruct;
@@ -23,7 +24,11 @@ mod tests {
     #[test]
     fn classic_c_structs() {
         // TODO: Instantiate a classic c struct!
-        // let green =
+        let green = ColorClassicStruct{
+            red: 0,
+            green: 255,
+            blue: 0
+        };
 
         assert_eq!(green.red, 0);
         assert_eq!(green.green, 255);
@@ -33,7 +38,7 @@ mod tests {
     #[test]
     fn tuple_structs() {
         // TODO: Instantiate a tuple struct!
-        // let green =
+        let green = ColorTupleStruct(0, 255, 0);
 
         assert_eq!(green.0, 0);
         assert_eq!(green.1, 255);
@@ -43,7 +48,7 @@ mod tests {
     #[test]
     fn unit_structs() {
         // TODO: Instantiate a unit-like struct!
-        // let unit_like_struct =
+        let unit_like_struct = UnitLikeStruct;
         let message = format!("{:?}s are fun!", unit_like_struct);
 
         assert_eq!(message, "UnitLikeStructs are fun!");
diff --git a/exercises/structs/structs2.rs b/exercises/structs/structs2.rs
index 328567f0..7e3dd7c7 100644
--- a/exercises/structs/structs2.rs
+++ b/exercises/structs/structs2.rs
@@ -5,8 +5,6 @@
 // Execute `rustlings hint structs2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[derive(Debug)]
 struct Order {
     name: String,
@@ -38,7 +36,11 @@ mod tests {
     fn your_order() {
         let order_template = create_order_template();
         // TODO: Create your own order using the update syntax and template above!
-        // let your_order =
+        let your_order = Order {
+            name: String::from("Hacker in Rust"),
+            count: 1,
+            ..order_template
+        };
         assert_eq!(your_order.name, "Hacker in Rust");
         assert_eq!(your_order.year, order_template.year);
         assert_eq!(your_order.made_by_phone, order_template.made_by_phone);
diff --git a/exercises/structs/structs3.rs b/exercises/structs/structs3.rs
index 4851317c..cebceb96 100644
--- a/exercises/structs/structs3.rs
+++ b/exercises/structs/structs3.rs
@@ -7,7 +7,7 @@
 // Execute `rustlings hint structs3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 #[derive(Debug)]
 struct Package {
@@ -29,12 +29,14 @@ impl Package {
         }
     }
 
-    fn is_international(&self) -> ??? {
+    fn is_international(&self) -> bool {
         // Something goes here...
+        self.sender_country != self.recipient_country
     }
 
-    fn get_fees(&self, cents_per_gram: i32) -> ??? {
+    fn get_fees(&self, cents_per_gram: i32) -> i32 {
         // Something goes here...
+        cents_per_gram * self.weight_in_grams
     }
 }
 
diff --git a/exercises/variables/variables1.rs b/exercises/variables/variables1.rs
index b3e089a5..a9d13f6a 100644
--- a/exercises/variables/variables1.rs
+++ b/exercises/variables/variables1.rs
@@ -5,9 +5,7 @@
 // Execute `rustlings hint variables1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
-    x = 5;
+    let x: u32 = 5;
     println!("x has the value {}", x);
 }
diff --git a/exercises/variables/variables2.rs b/exercises/variables/variables2.rs
index e1c23edf..ff9a7810 100644
--- a/exercises/variables/variables2.rs
+++ b/exercises/variables/variables2.rs
@@ -3,10 +3,9 @@
 // Execute `rustlings hint variables2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {
-    let x;
+    let x = 10;
     if x == 10 {
         println!("x is ten!");
     } else {
diff --git a/exercises/variables/variables3.rs b/exercises/variables/variables3.rs
index 86bed419..50cbe0f4 100644
--- a/exercises/variables/variables3.rs
+++ b/exercises/variables/variables3.rs
@@ -3,9 +3,8 @@
 // Execute `rustlings hint variables3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {
-    let x: i32;
+    let x: i32 = 0;
     println!("Number {}", x);
 }
diff --git a/exercises/variables/variables4.rs b/exercises/variables/variables4.rs
index 5394f394..2d056da9 100644
--- a/exercises/variables/variables4.rs
+++ b/exercises/variables/variables4.rs
@@ -3,10 +3,9 @@
 // Execute `rustlings hint variables4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {
-    let x = 3;
+    let mut x = 3;
     println!("Number {}", x);
     x = 5; // don't change this line
     println!("Number {}", x);
diff --git a/exercises/variables/variables5.rs b/exercises/variables/variables5.rs
index a29b38be..2a312acb 100644
--- a/exercises/variables/variables5.rs
+++ b/exercises/variables/variables5.rs
@@ -3,11 +3,10 @@
 // Execute `rustlings hint variables5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {
     let number = "T-H-R-E-E"; // don't change this line
     println!("Spell a Number : {}", number);
-    number = 3; // don't rename this variable
+    let number = 3; // don't rename this variable
     println!("Number plus two is : {}", number + 2);
 }
diff --git a/exercises/variables/variables6.rs b/exercises/variables/variables6.rs
index 853183ba..052a2f69 100644
--- a/exercises/variables/variables6.rs
+++ b/exercises/variables/variables6.rs
@@ -3,9 +3,8 @@
 // Execute `rustlings hint variables6` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
-const NUMBER = 3;
+const NUMBER: i32 = 3;
 fn main() {
     println!("Number {}", NUMBER);
 }
diff --git a/exercises/vecs/vecs1.rs b/exercises/vecs/vecs1.rs
index 65b7a7f8..5b84ffbc 100644
--- a/exercises/vecs/vecs1.rs
+++ b/exercises/vecs/vecs1.rs
@@ -7,11 +7,10 @@
 //
 // Execute `rustlings hint vecs1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
 
 fn array_and_vec() -> ([i32; 4], Vec<i32>) {
     let a = [10, 20, 30, 40]; // a plain array
-    let v = // TODO: declare your vector here with the macro for vectors
+    let v = vec![10, 20, 30, 40]; // TODO: declare your vector here with the macro for vectors
 
     (a, v)
 }
diff --git a/exercises/vecs/vecs2.rs b/exercises/vecs/vecs2.rs
index e92c970a..2b7354cf 100644
--- a/exercises/vecs/vecs2.rs
+++ b/exercises/vecs/vecs2.rs
@@ -7,13 +7,11 @@
 //
 // Execute `rustlings hint vecs2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
     for element in v.iter_mut() {
         // TODO: Fill this up so that each element in the Vec `v` is
         // multiplied by 2.
-        ???
+        *element = *element * 2;
     }
 
     // At this point, `v` should be equal to [4, 8, 12, 16, 20].
@@ -24,7 +22,7 @@ fn vec_map(v: &Vec<i32>) -> Vec<i32> {
     v.iter().map(|element| {
         // TODO: Do the same thing as above - but instead of mutating the
         // Vec, you can just return the new number!
-        ???
+        element * 2
     }).collect()
 }
 
diff --git a/rustlings b/rustlings
new file mode 160000
index 00000000..f2de12aa
--- /dev/null
+++ b/rustlings
@@ -0,0 +1 @@
+Subproject commit f2de12aa3443af2e989a045d9035294184d36eee