diff --git a/exercises/clippy/clippy1.rs b/exercises/clippy/clippy1.rs
index bdb5dd2c..eb712b28 100644
--- a/exercises/clippy/clippy1.rs
+++ b/exercises/clippy/clippy1.rs
@@ -6,12 +6,10 @@
 // check clippy's suggestions from the output to solve the exercise.
 // Execute `rustlings hint clippy1` for hints :)
 
-// I AM NOT DONE
-
 fn main() {
     let x = 1.2331f64;
     let y = 1.2332f64;
-    if y != x {
+    if (x - y).abs() < 0.00001 {
         println!("Success!");
     }
 }
diff --git a/exercises/clippy/clippy2.rs b/exercises/clippy/clippy2.rs
index 37af9ed0..4cdfbe75 100644
--- a/exercises/clippy/clippy2.rs
+++ b/exercises/clippy/clippy2.rs
@@ -1,12 +1,10 @@
 // clippy2.rs
 // Make me compile! Execute `rustlings hint clippy2` for hints :)
 
-// I AM NOT DONE
-
 fn main() {
     let mut res = 42;
     let option = Some(12);
-    for x in option {
+    if let Some(x) = option {
         res += x;
     }
     println!("{}", res);
diff --git a/exercises/standard_library_types/arc1.rs b/exercises/standard_library_types/arc1.rs
index 9784e84a..f5e99bf1 100644
--- a/exercises/standard_library_types/arc1.rs
+++ b/exercises/standard_library_types/arc1.rs
@@ -4,17 +4,16 @@
 // somewhere. Try not to create any copies of the `numbers` Vec!
 // Execute `rustlings hint arc1` for hints :)
 
-// I AM NOT DONE
-
 use std::sync::Arc;
 use std::thread;
 
 fn main() {
     let numbers: Vec<_> = (0..100u32).collect();
-    let shared_numbers = // TODO
+    let shared_numbers = Arc::new(numbers);
     let mut joinhandles = Vec::new();
 
     for offset in 0..8 {
+        let child_numbers = shared_numbers.clone();
         joinhandles.push(thread::spawn(move || {
             let mut i = offset;
             let mut sum = 0;
diff --git a/exercises/standard_library_types/iterators2.rs b/exercises/standard_library_types/iterators2.rs
index 837725f0..d25fac89 100644
--- a/exercises/standard_library_types/iterators2.rs
+++ b/exercises/standard_library_types/iterators2.rs
@@ -7,16 +7,19 @@
 //         Try to ensure it returns a single string.
 // As always, there are hints if you execute `rustlings hint iterators2`!
 
-// I AM NOT DONE
-
 pub fn capitalize_first(input: &str) -> String {
     let mut c = input.chars();
     match c.next() {
         None => String::new(),
-        Some(first) => first.collect::<String>() + c.as_str(),
+        // TODO: Check why we would use collect() here?
+        Some(first) => first.to_uppercase().to_string() + c.as_str(),
     }
 }
 
+pub fn capitalize_words(input: Vec<&str>) -> Vec<String> {
+    input.iter().map(|word| capitalize_first(word)).collect::<Vec<String>>()
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -26,6 +29,7 @@ mod tests {
     #[test]
     fn test_success() {
         assert_eq!(capitalize_first("hello"), "Hello");
+        assert_eq!(capitalize_first("é"), "É");
     }
 
     #[test]
@@ -37,14 +41,14 @@ mod tests {
     #[test]
     fn test_iterate_string_vec() {
         let words = vec!["hello", "world"];
-        let capitalized_words: Vec<String> = // TODO
+        let capitalized_words: Vec<String> = capitalize_words(words);
         assert_eq!(capitalized_words, ["Hello", "World"]);
     }
 
     #[test]
     fn test_iterate_into_string() {
         let words = vec!["hello", " ", "world"];
-        let capitalized_words = // TODO
+        let capitalized_words = capitalize_words(words).join("");
         assert_eq!(capitalized_words, "Hello World");
     }
 }