diff --git a/tracks/typescript/exercises/rna-transcription/mentoring.md b/tracks/typescript/exercises/rna-transcription/mentoring.md
index 991138483..40b924f1f 100644
--- a/tracks/typescript/exercises/rna-transcription/mentoring.md
+++ b/tracks/typescript/exercises/rna-transcription/mentoring.md
@@ -42,7 +42,7 @@ return sequence.replace(/./g, (nucleotide) => /* */)
 
 Variations include replacing only the "known" nucleotides:
 ```typescript
-sequence.replace(/[CGAT]g/, (nucleotide) => /* */)
+sequence.replace(/[CGAT]/g, (nucleotide) => /* */)
 ```
 
 ## Common suggestions