diff --git a/exercises/23_conversions/using_as.rs b/exercises/23_conversions/using_as.rs
index c131d1f..dff453b 100644
--- a/exercises/23_conversions/using_as.rs
+++ b/exercises/23_conversions/using_as.rs
@@ -5,7 +5,7 @@
 fn average(values: &[f64]) -> f64 {
     let total = values.iter().sum::<f64>();
     // TODO: Make a conversion before dividing.
-    total / values.len()
+    total / values.len() as f64
 }
 
 fn main() {