diff --git a/tcr-roman-numerals/src/main/java/fr/ippon/kata/numeral/Numerals.java b/tcr-roman-numerals/src/main/java/fr/ippon/kata/numeral/Numerals.java
index e77b413d3e35dfb1d9bdef61a1a4aca3fd5f2e5c..9ae95cbd7ad4bfba429a2158ea1183b987af797c 100644
--- a/tcr-roman-numerals/src/main/java/fr/ippon/kata/numeral/Numerals.java
+++ b/tcr-roman-numerals/src/main/java/fr/ippon/kata/numeral/Numerals.java
@@ -23,6 +23,7 @@ public class Numerals {
     conversions.put(4, "IV");
     conversions.put(5, "V");
     conversions.put(9, "IX");
+    conversions.put(10, "X");
 
     return conversions;
   }
diff --git a/tcr-roman-numerals/src/test/java/fr/ippon/kata/numeral/NumeralsTest.java b/tcr-roman-numerals/src/test/java/fr/ippon/kata/numeral/NumeralsTest.java
index 4fb0d0e5b085c88b8142b614e001fa2838a2d5d4..3858f66cceed2384b5d2cebffb6a5f6601f642de 100644
--- a/tcr-roman-numerals/src/test/java/fr/ippon/kata/numeral/NumeralsTest.java
+++ b/tcr-roman-numerals/src/test/java/fr/ippon/kata/numeral/NumeralsTest.java
@@ -40,4 +40,9 @@ class NumeralsTest {
   void shouldConvertNineToIX() {
     assertThat(Numerals.toRoman(9)).isEqualTo("IX");
   }
+
+  @Test
+  void shouldConvertTenToX() {
+    assertThat(Numerals.toRoman(10)).isEqualTo("X");
+  }
 }