diff --git a/src/main/java/kyu6/NumberInExpandedForm.java b/src/main/java/kyu6/NumberInExpandedForm.java
index e64151c..bb35662 100644
--- a/src/main/java/kyu6/NumberInExpandedForm.java
+++ b/src/main/java/kyu6/NumberInExpandedForm.java
@@ -8,6 +8,9 @@ public class NumberInExpandedForm {
     //6 https://www.codewars.com/kata/5842df8ccbd22792a4000245/train/java
 
     public static String expandedForm(int num) {
+        if (num == 0) {
+            return "0";
+        }
         StringBuilder result = new StringBuilder();
         char[] chars = String.valueOf(num).toCharArray();
         for (int i = 0; i < chars.length; i++) {
diff --git a/src/test/java/kyu6/NumberInExpandedFormTest.java b/src/test/java/kyu6/NumberInExpandedFormTest.java
index 08cc5a3..0ffe3ce 100644
--- a/src/test/java/kyu6/NumberInExpandedFormTest.java
+++ b/src/test/java/kyu6/NumberInExpandedFormTest.java
@@ -17,6 +17,11 @@
 import static kyu6.NumberInExpandedForm.*;
 @Tag("smoke")
 public class NumberInExpandedFormTest {
+    @Test
+    void zeroShouldRemainZero() {
+        assertEquals("0", expandedForm(0));
+    }
+
     @Test
     void smokeTestsShouldExecuteApi() {
         quality.SmokeMethodTestHarness.verify(kyu6.NumberInExpandedForm.class);