diff --git a/exercises/alphametics/src/lib.rs b/exercises/alphametics/src/lib.rs
index 93a2f3646..5e456202d 100644
--- a/exercises/alphametics/src/lib.rs
+++ b/exercises/alphametics/src/lib.rs
@@ -1,5 +1,5 @@
 use std::collections::HashMap;
 
-pub fn solve(_: &str) -> Option<HashMap<char, u8>> {
-    unimplemented!()
+pub fn solve(input: &str) -> Option<HashMap<char, u8>> {
+    unimplemented!("Solve the alphametic {:?}", input)
 }
diff --git a/exercises/book-store/src/lib.rs b/exercises/book-store/src/lib.rs
index af1e61039..306ed9dbe 100644
--- a/exercises/book-store/src/lib.rs
+++ b/exercises/book-store/src/lib.rs
@@ -1,3 +1,3 @@
-pub fn lowest_price(_: &[usize]) -> usize {
-    unimplemented!()
+pub fn lowest_price(books: &[usize]) -> usize {
+    unimplemented!("Find the lowest price of the bookbasket with books {:?}", books)
 }
diff --git a/exercises/crypto-square/src/lib.rs b/exercises/crypto-square/src/lib.rs
index cf84ac82f..83de47493 100644
--- a/exercises/crypto-square/src/lib.rs
+++ b/exercises/crypto-square/src/lib.rs
@@ -1,3 +1,3 @@
-pub fn encrypt(_: &str) -> String {
-    unimplemented!()
+pub fn encrypt(input: &str) -> String {
+    unimplemented!("Encrypt {:?} using a square code", input)
 }
diff --git a/exercises/decimal/src/lib.rs b/exercises/decimal/src/lib.rs
index 0c2bddc81..77a491359 100644
--- a/exercises/decimal/src/lib.rs
+++ b/exercises/decimal/src/lib.rs
@@ -4,7 +4,7 @@ pub struct Decimal {
 }
 
 impl Decimal {
-    pub fn try_from(_: &str) -> Option<Decimal> {
-        unimplemented!()
+    pub fn try_from(input: &str) -> Option<Decimal> {
+        unimplemented!("Create a new decimal with a value of {}", input)
     }
 }
diff --git a/exercises/poker/src/lib.rs b/exercises/poker/src/lib.rs
index e34909fec..3e91bafea 100644
--- a/exercises/poker/src/lib.rs
+++ b/exercises/poker/src/lib.rs
@@ -2,6 +2,6 @@
 ///
 /// Note the type signature: this function should return _the same_ reference to
 /// the winning hand(s) as were passed in, not reconstructed strings which happen to be equal.
-pub fn winning_hands<'a>(_: &[&'a str]) -> Option<Vec<&'a str>> {
-    unimplemented!()
+pub fn winning_hands<'a>(hands: &[&'a str]) -> Option<Vec<&'a str>> {
+    unimplemented!("Out of {:?}, which hand wins?", hands)
 }